Thank you James…over the years you have really taught us how to be more discerning with respect to choosing and working with our equipment.🔭😊❤️
@Aero19612
2 жыл бұрын
Thanks for watching!
@cdavidhord
2 жыл бұрын
I'm learning and you are helping me.
@Aero19612
2 жыл бұрын
Thanks for watching, Dave!
@NeilCorke
2 жыл бұрын
Another really helpful video James. I’ve got a ZWO M68 OAG with the 290MM mini which is proving difficult to get good focus with. Think I’ll try this comparison!
@Aero19612
2 жыл бұрын
Hey, Neil. I assume you mean focusing the guide camera. Have you tried focusing during the day? I set mine up by focusing on the wood grain in the fence. Lots of contrasty lines to use. Once you get the imaging and guide camera focused, that's it. It'll work at night too. Good luck!
@cryptojihadi265
Жыл бұрын
Just got my GT71 with the 50mm unguide. Using my ZWO 462MC on an AP MACH2GTO mount I was right in the .3 to .4" total error range. Really sweet and simple setup.
@Aero19612
Жыл бұрын
Excellent guiding performance! Sounds like a winner of a setup. Congratulations!
@JonnyBravo0311
2 жыл бұрын
I run the GT81 with the Uniguide 50. Guide cam is a QHY 5L-II M and main cam is a ZWO ASI294MM Pro. Rides on a CEM40. I have zero complaints on the guiding performance. Best I've ever seen is in the low 0.3"/px range. Typically I'm around the same level of performance you show in the video... between 0.5 and 0.7. In any case, that's overkill since my imaging scale goes from 1.25"/px to 2.5"/px depending on whether I'm running the 294 in its unlocked or default modes. In my opinion, as long as you're getting round stars in your subs, your guider is doing its job. Just like with sampling rates, people tend to get hung up on the numbers and lose the forest for the trees.
@Aero19612
2 жыл бұрын
Totally agree! The kind of numbers I'm getting I would be happy with when imaging at 2200 mm. There are two issues: (1) Is the guiding good enough for imaging and (2) What is the guiding performance of the system. When imaging, we should be concerned about (1) and not so concerned about the "/pixel if the guiding is good enough. In this video, I'm more interested in the academic question: How does the Uniguide measure up to an OAG (or, can I actually tell the difference)?
@dawnpaulandelizabethromero3458
2 жыл бұрын
Hi James, I was referred to you by another youtuber, and your videos are very well done! I appreciate them! I want you to know that the main reason for me wanting an oag is to reduce the torque moment on my mount. My Celestron 80 mm guidescope is almost 2 ft from the axis of the declination of the mount. That, Plus 70 lb of payload and 90 lb of counterweight are taxing the mount. Also thanks to your video, I realized that the 440 mm focal length of my guide scope pales in comparison to the 2000 mm focal length of my RC scope. I think a good compromise would be to put the oag on my 770 mm refractor. I know I'll just have to test and see!
@Aero19612
2 жыл бұрын
Welcome to the channel! I bought my first OAG (for my C9.25 SCT) after doing the analysis that showed a big reduction in the demand on RA torque (that big Celestron guide scope sitting on my SCT far from the RA axis. Holy cow!)…then it took me 2 years to get up the nerve to use it! Haha. Now, I use OAGs with all 4 of my scopes from 250 mm to 2280 mm. Not going back to guide scopes. Good luck!
@lphilpot01
2 жыл бұрын
I'm not yet (?) an imager, at least until I get that Star Adventurer 2i out of the closet and under night skies. :-) But I still enjoy your very informative videos. Great job.
@Aero19612
2 жыл бұрын
Thanks, Len. It’s more fun to watch someone else making the mistakes than making them yourself. Time to start earning those “imager” scars. Clear skies!
@lphilpot01
2 жыл бұрын
@@Aero19612 Yep, I guess so. After 34 years of collecting 'visual scars' i guess I need some more frustration. LOL :-)
@avipatil8400
2 жыл бұрын
Just my 2 cents. I think comparing cost and guiding should have used the same guiding camera. I think with guidescope you can get away with cheaper camera. As to guiding may be multi star guiding has something to do with guiding. I think you will find that multi star guiding with OAG (not always possible) will result in a similar guiding performance as guidescope.
@Aero19612
2 жыл бұрын
Hey Avi. A true comparison is almost impossible given all of the variables. I think if the guide camera is providing adequate SNR, it's good enough. I think the ASI120MC was "good enough" for this test, but I certainly would not recommend using a color camera for guiding. When I first started out in AP, I used my DSLR for DSO imaging and a color camera (similar to the 120MC) for planetary or as a guide camera when DSO imaging. Saves money, but not ideal. My simple test here gave similar results for the Uniguide and the OAG. If you're imaging at 2000mm with an OAG, you definitely want a sensitive (more expensive) guide camera because your available stars will be very few indeed. Thanks for watching!
@rockhauling.d.4816
Жыл бұрын
For sure that scope is loaded with cables hehe. I have a question again Why do you have to use two guiding scope at the same time ,is that just comparison?
@Aero19612
Жыл бұрын
Yes, just for comparison. My go-to guiding method is the off-axis guider.
@blueobject
2 жыл бұрын
Awesome video. Curious how the graphs look side by side?
@Aero19612
2 жыл бұрын
Hey, Marty. Of course the graphs would not be “identical” since they represent a highly random process. I do proper statistical analysis of guiding results in other videos, but haven’t taken the time to do that with this scope VS the OAG. That said, if you’re inclined to use a scope like this, I highly recommend it. I made the jump to the OAG for all of my scopes, so don’t really use this little guide scope for my imaging projects. It’s nice - especially if you have a William Optics scope with a handle that’s compatible with this vixen base. Thanks for watching!
@foxglovemead
2 жыл бұрын
Good test - thanks. I would have been tempted to use the ASI290 camera in both setups so that the single variable is guiding method? Flexure with Uniguide scope should be absolute minimum. Not sure ZWO OAG is firmly attached (holding prism) and camera attachment (unlike EP with two 90 degree screws) is as good? How do you set prism height e.g. start at highest setting and work down until you get something? Or look at light cone on main sensor and establish a lower limit? The beauty of an OAG setup paired with a main camera is that it is a “unit” e.g. when both cameras are in focus it will work with any scope e.g. sufficient extension tubes in front of OAG. Can you measure and correct any “play” in ZWO OAG by evaluating camera image centres with angle of scope and flipping scope to see relative movement? Would a cable tie holding the 290 cable to something firm and either a 2nd EP screw or blob of silicone help resist any movement? Of course it may not be an issue except if you resumed after a Meridian flip? Simon
@Aero19612
2 жыл бұрын
Hey Simon. Yes, using the ASI290 for both setups might have been a better test. I just didn’t want to disturb my 290 since it is focused in the OAG and if I removed it I’d have to refocus and rerun a PHD calibration. Lazy vs science, lazy wins. Haha. I haven’t noticed any “loose” issues with the OAG. I think it does have two set screws at 90 deg. I can’t remember how I set the prism height. You want it as far out as possible as long as your guide camera sensor isn’t in a shadow. Once you set the guide sensor distance to the OAG prism, you can test different heights of the unit. I have an OAG shadow in my images, but flats (mostly) take care of it. Thanks for watching!
@foxglovemead
2 жыл бұрын
@@Aero19612 I only read ZWO OAG manual and noticed only one screw for camera. It was a suggestion to be 100% sure it's not loose. My QHY has two screws at 90 degrees. Normally an EP requires fixing in two axis to prevent a tilt, so being secure is a priority and flexure is preventing any relative movements? QHY comes in different sizes (ZWO also with M68) - I have the medium version with M54 . I want to get the prism completely outside the FOV of the main sensor to avoid shadows but also internal reflections. Cone of light means that the prism has to further out to clear the main sensor - but small throat size (and extension tubes in front of the prism) and/or limited image circle don't help? On a flat I do see a shadow so perhaps I'm not yet there. Simon
@Aero19612
2 жыл бұрын
Ahhh, yes. One set screw for the camera. There are two at 90 deg for the prism stalk. Yes, I've often wondered if I'm getting some tilt with that one screw. It seems to hold the camera well but I should check it more often. especially with colder weather. If you still see stars in the OAG shadow, flats will (mostly) compensate for that. If you have a smaller sensor (like my ASI1600) in a scope with a full frame image circle, you might be able to completely push the prism out of view. If you have a full-frame camera, then probably not. Good luck, Simon!
@foxglovemead
2 жыл бұрын
@@Aero19612 Compare image shift between cameras before/after Meridian flip at low/high Azimuth to see if it is a problem? SGP Pro can find target again after Meridian flip. Perhaps a cable tie on USB lead to OAG body would improve stability?
@SimonT65
2 жыл бұрын
Another nice video James. Sharpcap is up to version 4.0.8365 if you weren't aware?
@billblanshan3021
2 жыл бұрын
Yep, and with overshoot focusing.
@Aero19612
2 жыл бұрын
Thanks, Simon! I was NOT aware. I'll download it now.
@Aero19612
2 жыл бұрын
Really!? I need to dig into all the features of Sharpcap. I don't tend to use it much except for "experimenting" and planetary imaging.
@billblanshan3021
2 жыл бұрын
@@Aero19612 yes sir, I had Robin add it in a few months ago and works well. I am trying to get him to have a one-click auto focus feature put in similar to NINA. I hope he add this as it would be a big help especially to planetary imaging
@DiegoGomez-px6lh
2 жыл бұрын
Hi James! Thanks again for sharing your experiences with us! Have learned a lot from your videos! Could you please comment about the image quality of the Uniguide 50 (for example chromatic aberration, etc)? How about dovetail, is it well attached to the tube?? Thanks!
@Aero19612
2 жыл бұрын
Thanks for watching, Diego! I'm glad you're finding some the content here useful. The Uniguide 50 is a guidescope, of course, so there's no expensive optics here. It's fair. I really didn't look to closely at Moon image I show in the video. It's pretty good, but I wouldn't use it for imaging.
@DiegoGomez-px6lh
2 жыл бұрын
Thanks James for your comments. I am not thinking in using the Uniguide for imaging but for guiding. The reason why I asked about the imaging quality is because my current guidescope has a lot chromatic aberration. Also, I wanted to know how sturdy it was when attached to the main scope. Thanks!
@Aero19612
2 жыл бұрын
Ha, I guessed as much! The Guide scope has a very solid connection because the Vixen base is continuously molded to the scope body (no guide rings). I didn't save any of the pictures I took through the scope. Next time I'm out, I'll see if I can grab some pictures.
@Dorkyand40
2 жыл бұрын
james im sold on this setup after messing with a rasa 8 for the past year im over it. so how did you end up mounting the plate and power box advanced with this setup? is it mounted to the celestron bar? also where did you get that plate again? thanks for all you do
@Aero19612
2 жыл бұрын
This setup is a bit clunky because I also have a guidescope attached for testing purposes. Normally, I just use the OAG. I have two perforated aluminum plates that I bought from Metals Depot (I think). They're 1/16" thick with 1/4" holes. You can specify a size. In my normal arrangement, I screw one plate to the top of the handle and velcro the Power Box to the plate.
@Dorkyand40
2 жыл бұрын
@@Aero19612 yes thank you. One last question is how do you have the sheet mounted here in a vertical position? I would assume some kind of L brackets coming from the celestron rail but can’t see.
@Aero19612
2 жыл бұрын
@@Dorkyand40 Yep. I found some little L-brackets on Amazon with a 1/4" hole in each leg. Let me know how it goes. Finally making use of all those "skills" playing with the Erector Set as a kid.
@Dorkyand40
2 жыл бұрын
@@Aero19612 you do a dang good job man. I enjoy your methods and videos tremendously. You’ve taught me a lot. I’ll let you know how it all goes here soon :)
@jlecomte0719
2 жыл бұрын
Wait, guiding performance cannot be determined by what you see in PhD2! The only way to determine it is to measure the size and shape of the stars in an image taken from the main imaging scope. Indeed, I get amazingly good guiding results with my guide scope according to PhD2, but the stars in my images are fat and elongated due to flexure. On the other hand, I get sharp and round stars when guiding with an OAG. Am I missing something? Thanks for your videos, the content you put out is really great!
@Aero19612
2 жыл бұрын
Well, I don't totally agree. Guiding performance is best represented in PHD2 arc-sec RMS. Guiding performance is affected by: seeing, mount mechanical, guide camera imaging scale, and PHD2 algorithm parameters. Here's where I agree with you: When we're imaging (not doing an academic study like I am in this video), your guiding performance just needs to be "good enough" based on your focal length and star shapes as you say. If it's good enough, better guiding doesn't help and there's no point in whining about the arc-sec RMS. I would be totally happy with 0.7 arc-sec RMS for my 2200mm SCT. Thanks for watching, Julien!
@Aero19612
2 жыл бұрын
Ooops. Missed a point you are making. I wouldn't call "flexure" a guiding issue. So, in that sense, your guiding is in fact very good (according to PHD2) but your images aren't reflecting that because some other effect (flexure in your case) is introducing image issues. Guiding is not the only determining factor for image quality. You found one of the other non-guiding factors: flexure. My video is only concerned with a guiding comparison.
@jlecomte0719
2 жыл бұрын
Thanks for taking the time to respond to my comment. OK, it makes sense now. Thank you again for the very informative videos!
@MegaDon2006
2 жыл бұрын
@@Aero19612 Your videos are very informative. Thank you for these. I would think flexure cannot be decoupled in the analysis between OAG and guide scope. One would think flexure effects are negated in OAG vs using a guide scope. Perhaps HFD comparison between the two would be a good test, obviously this would have to be done on the same night and in relatively similar dec/RA of the chosen star? Thoughts?
@Aero19612
2 жыл бұрын
Totally agree that an advantage of an OAG is avoiding flexure. That said, flexure is only a problem with very long exposures (or very poorly attached guidescope). I also don't think flexure affects guiding per se. When I think of "guiding", I'm mostly thinking and "rapid" back and forth motions due to seeing and mechanical imperfections in the gear train. Flexure causes a slow drift that will only (mostly) be visible when imaging at a long focal length for a long exposure time (~15 min). Thanks for watching, Tushar!
@Navvartheone
2 жыл бұрын
Thanks for the comparison, the visual element really helped compared to just reading about it on a forum. As someone inexperienced who is looking to get the little brother of your scope (GT71 + FF/FR) and is also looking to get into autoguiding for the first time, do you have any tips or pointers as to the assembly when using an OAG? I already have a planetary camera (ASI485), but I've no idea how well it'd do at 336mm FL with an OAG compared to the 200mm guidescope - what would be your choice if you were in my shoes?
@Aero19612
2 жыл бұрын
Hi Fredrik. You don't have to worry about an OAG much at 336 mm. The ASI485 should be OK. The sensor is much larger than a typical OAG prism, so that is good. It is a color camera, which is not ideal for sensitivity of a guide camera (in my video, I had to use my color camera in the guide scope and it worked just fine). Give your 485 a test. If you're not happy (I think it'll work just fine), you can get a dedicated guide camera later (e.g., the ASI290MM mini). Have fun with your new scope when you get it! Hope that helps and thanks for watching!
@Navvartheone
2 жыл бұрын
@@Aero19612 The idea of a guide scope does sound more appealing as a beginner (less fiddly), which is what I think I'll ultimately go with. I also have a 5'' Mak (1500mm FL, F/11.8) that I've had for years but didn't start imaging with until very recently, which was also partly the reason I asked about the OAG (should've pointed that out in my initial comment) - at that FL however, I imagine the ASI485 would struggle with guiding, and something like the 120/290 mini would be more adequate. I realize the Mak isn't very ideal for imaging DSO's, but being able to produce an image of M81 with it is what got me into the hobby to start with, whether that's a positive or negative I guess my bank account will be the judge of...hah. Thanks for all the content you produce, I really like your style of presentation.
@Aero19612
2 жыл бұрын
No brainer! It's a positive for your mind (a negative for your wallet). This hobby keeps you off the streets at night. Yes, as you go up in focal length, you will want a more sensitive dedicated guide camera. Your OSC may still be fine at 1500mm. You can always try binning the guide image for added sensitivity. In other words, use the heck out of what you've got before buying something new. Have fun, Fredrik!
@anata5127
2 жыл бұрын
These calculations are great, if differential flexure is zero.
@febsat
2 жыл бұрын
Geez, hard to believe ZWO would leave you (and others) hanging out in the wind with that 'paperweight'. I guess astrophotography has picked up so much that potential customers are running to their door to buy astro items; so what if they have a few disgruntled customers... They need more competition.
@Aero19612
2 жыл бұрын
Agree. ZWO has very little competition. There's QHY, but no real apples to apples competitor.
@NeilCorke
2 жыл бұрын
After the response I got ZWO regarding the USB port coming loose on a 6200MM about three months after buying it I don’t have any difficulty at all believing that!
@febsat
2 жыл бұрын
@@NeilCorke OMG! A 6200 is not chump change. They are feasting on the fact that so many people have taken up this hobby. A cash cow for them to milk at will. Prices are steep, but the alternatives are few. Wishing you many clear nights for 2022.
@NeilCorke
2 жыл бұрын
@@febsat they tried to tell me I needed to ship it back to china at my expense, and either complete a bogus customs declaration for a 50 dollar webcam, or pay import duties on the 4k value and they would return it repaired within 2-3 months. Needless to say, that was nothing like the resolution I was looking for, and fortunately as I didn’t buy it from them directly, was able to convey a more realustic solution to the dealer I bought it from. In the end they sent a new main board to fit myself, which was very easy. This was also what I requested initially, and they refused point blank.
@febsat
2 жыл бұрын
@@NeilCorke cheers to your dealer. The thought of shipping something to China for repair would be a show stopper for me. I prefer to buy through reputable dealers. Sure, there can be a few deals to be found, but not without risk.
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