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I've yet to notice the EOFB in the APM. Of course, I'm generally not under dark skies like Mt. Pinos where I might be able to detect it.

I recomposited my 12mm to 14m UWA eyepiece ruler images together so it's easier to see the differences in presentation. It's also obvious which have objectionable SAEP. All are sharp to the edge at f/6.

I find the APM 12.5 to have noticeable and objectionable edge of field brightening. That's too bad, since otherwise it's fine. The 12.5mm Morpheus is a great eyepiece--sharp, great contrast, easy to use. It's also lighter than the APM. It's an easy choice, IMO.

I use the mount so infrequently that way, meaning manually with slow motion controls in a not-motorized session, and when I do I am turning the knobs very slowly and very little anyway that I am not concerned. I have spoken to Derek on the phone about using the slow motion controls with the motors installed and he said basically not to turn them with the power on because the belts can be damaged but that I could use them with the mount powered off if I am OK with the resistance (which I am). He never said anything about turning them with the motors off being bad for the mount or that it was a frying risk, that it simply was not as fluid as an experience as it was before I installed the motor kit on my mount. I may be wrong and I may have misinterpreted what he said, but I never felt that he was telling me not to use the slow motion controls with the mount powered off, but instead he was telling me that there would be resistance in the system where before there wasn't. I think that the verbiage from the manual specifically "If the mount is powered off the slow motions can still be used but..." strongly implies that it is fine to do so they would not say that they could still be used if it was bad to do so, and that "therefore it is recommended that the slow motions are only used manually when the mount is powered on and the motors are turned off on the webpage" is telling us that if the mount's slow motion controls need to be used with the mount powered on that the motors have to be turned off first before doing so.

From whay I've read/seen so far, I understand that the principle behind the tri-Bahtinov maskmis that collimation (tilted mirror) results in a tilted focal plane. But so, in a way, does tilt in the focuser or camera. So I wonder if it's even possible to distinguish one from the other. I will test more when astro darkness returns in August. Atm my telescope is in summer storage.

Hello and apologies if this is a silly question. Am finding all the advice and insight really helpful but am still struggling. I live in the east midlands in the UK and have been trying to observe since January. Now that the weather has improved I have been getting my Skywatcher 130m EQ2 out to try and see things. Although I have seen great detail of the moon, I have not managed to see much else. I accept this likely due to my lack of experience but I was wondering whether due to the time of year I am probably not able see much between 9:30 and 10:30 at night and need to wait until a lot later. At this stage I really want to see the planets before exploring anything else. Grateful for any advice. Cheers

Hi everyone, I have run into a bit of trouble after taking apart my C8 to install an EAF electric focuser. the previously installed feathertouch focuser isn't compatible with the EAF and after taking the feathertouch of the OTA, I am left with nothing but the bare focusing bolt that's attached to the mirror. I can't attach the EAF to that and I can't find the original focuser knob from Celestron anywhere as a spare part. I want to ask the community if anybody has one of these flying around their workshop maybe after upgrading to a feathertouch. My OTA was purchased with the feathertouch many years ago so I never had the original. I am a bit lost at what else to do, other than to try and source a original focuser...

Well after some experimenting I have decided to go back to LCG at gain 100. Looks so much better to anyone else seeing this post.

I've never had any bigger problems with tilt on this camera. The only tilt-like effects are related to a bent and it's always visible on the edge aimed down during the session. Here is a masterLight as example with an Askar FMA230: The stars aren't perfect, but take please into account that my Askar FMA230 has its back focus equal to 52.5mm instead of 55mm, so I stopped selecting spacers at an acceptable point which is fixable by a BlurXterminator. Here is the same camera attached to an Altair 102 EDT Triplet APO with a dedicated x0.8 reducer, distortion is neglectable (at least for me).

Also be sure without the air connected to set your zero position on the hand controller, slew so your scope is pointing roughly on top and in line with mount at the pole star, then set zero position. Then when you connect your air, one of the first things I do is "goto home", it shouldn't move as it's already in the zero position, if the alignment is correct it should also return the scope back to the zero position you set on the hand controller if you've slewed it to anywhere else prior. At times I've had the air "reset" the home position causing all sorts of goto errors including causing the scope to kamikaze and point toward the ground. Note usually with the air connected to the hand controller, you don't need to touch the hand controller thereafter, all the control is done in the air app.

I assume you are talking about this thread ? If so, as michael has referred, just know the limitations and don't expect the incredible images you see taken with large SCT's and Dobs. A picture says a 1000 words, so to give you an idea, the following links are to images with my Starfield 102ED refractor + 2x barlow + ASI-585MC. Jupiter and Saturn , Jupiter with Ganymede shadow animation . Remember that that's nearly double the focal length of your 72ED and, crucially, using a high-speed planetary camera. The effective focal length was around 1500mm if I recall correctly, and the ROI reduced to increase frame rate. I've not tried it with a DSLR. Here is my rig I used to image the Moon with the 72ED from indoors, and I note I stated I didn't have enough focuser travel to achieve focus with a barlow. And here is my 102 ED. The barlow is a 1.25" nose piece fit, and both scopes come with a 1.25" clamp fit. Planetary imaging is completely different to DSO imaging; this superb FAQ over on CN helped me a lot in getting started. Pay particular attention to section 6 to establish the best barlow length to suit your scope, camera and seeing conditions. Presently, most of the planets aren't visible. Take a look in the Planetary imaging section too; you won't find many posts being made now, but it is a hive of activity during the season. Hope that helps.

Ah no, forgot. I was racing cloud.

Yes, I have a lot of thin plastic spacers starting at 0.2mm and also three paper ones, each around 0.1mm, I described experiments with them earlier in this thread. I reached a compromise between the coma and radially elongated stars at 1.2mm spacer in total, but I used filter then, I think it was the L-eXtreme. I have to check it again without filters, but not tonight, the setup is at home now due to clouds. I'm happy to see that the Sigma lens is OK, I considered returning it under warranty... There is a very interesting method of setting the iris permanently: Based on a following CN thread I attached the 6D body, set a BULB mode, pressed the shutter release button and... detached the body - the iris remains in the F/1.8 position. That's a great trick! https://www.cloudynights.com/topic/837147-sigma-art-40mm-14-canon-mount-no-aperture-ring/

Great review. It is one of the best value eyepieces on sale. I wouldn't swap mine for anything. I've sold all my high power eyepieces.

https://amzn.eu/d/3kv0drE Sloppy is a good word to use. As soon as you go to lock it down PA is lost! Yes. I had to do a bit of a fix as you say to get it working. I bought a M8 x 20mm thread with a push button ratchet that worked well. I know it’s for fun in EQ mode but I have got some decent images from it. The wedge is just frustrating and flimsy as you know. I take it this is the Ioptron one… https://www.firstlightoptics.com/ioptron-mount-accessories/ioptron-alt-azimuth-adjustable-base.html?gad_source=1&gclid=CjwKCAjw26KxBhBDEiwAu6KXtxoA7i09_s7AiV0qKB67t_C7gp52irh5ZkZ77biFQv4mbmP8is7FvRoCQH0QAvD_BwE Seen the Omegon polar wedge as well if it’s any good but starting to see £200!! Seems to me that I will have to have patience and get a used WO wedge. 🙄

Have you got any thin spacer rings to put onto the back of the lens adaptor prior to the camera, that's what I'd try next. But before that, just because you don't need anything else to test it, try stopping the lens down at each f ratio and see if it improves. Also I assume you've already checked your 2600 tilt adjustment plate is square to the body and not tilted in any way?

There is not too much to measure, only the ZWO filter drawer. I base on the Sigma 44mm flange distance and the ASI 17.5mm back focus. The ZWO must be the remaining 26.5mm long and it is indeed. I use a high-class vernier caliper which is older than me. I love to use it, even if I have two digital ones.

Great review Michael and certainly yes ,100% a bargain of the century. To put it mildly if one makes use of the 0.5mm settings between the main stops one is getting a very good multi FL EP which accrues to approx £8 for each FL of 0.5mm (if bought at the bargain price of £80). Purists will still want their fixed FL favourite EP's but for travelling and weight an all in one EP, for those on a budget a must have EP which with a pair of quality EPs in the 15 - 30mm range will be all that is required.

I got one today in the post. A nice 3D printed tri bahtinov mask from Ebay seller astrobyorlando. Some testing on my C8 Edge tonight. I've never owned an SCT before now but I got damn as near perfect collimation within a few minutes with this mask. I wasn't far out to begin with but it looks like it does the trick? It may be different with a newt as there are different angles involved?

Oh, yes, the lens is 1.3kg heavy, so I bought a dedicated ring holding it while the Canon or the ASI camera (both around 700g) is just attached to the lens. I wouldn't be worried if I saw marks of the tilt: pinpoint stars along one edge and comas on the opposite edge, but that's not the case.

I would note the ZWO Ef adaptor likely isn't mounted square so will cause an element of tilt, I get it on all my SY135s, the weight of the lens doesn't help. A lot of people have to shim to get it right. Make sure you're measuring with a good quality Vernier caliper too either a manual one or digital, measure each component separately, then again when assembled.

Originally, I wanted to buy a 50mm lens. When I made some research I found that the 50mm lenses are as you wrote above. Then my attention focused on a Tamron 35mm and the Sigma 40mm Art. I had to read a lot to find that the Sigma is outstanding even at F/1.4, better than the Tamron. It's worth the price. I measured the optical path of the ZWO EF/M42 filter drawer using a vernier caliper.

This makes me want more TV items, my wallet will never forgive me! Thank you FLO for posting this, in this image I see a group of great people beaming with passion for what they do, fantastic!.

Yes it should be the opposite. I'm surprised it works pin point to the edge of a FF sensor, most reviews of lenses where they state they're good for astro and you look at the edges they look awful, from experience all the lenses I've used distort at the edges even on FF lenses, though I've never used an Art. How have you measured your distance?

I have to admit that I didn't think about it. But today I didn't use any filter.