XavierL

I did manage to get first light on the new scope tonight and shot the same target for comparison.

I quickly processed a stack of 10x2min exposures and did the same thing with the old scope in order to compare. The new scope looks a lot better across the field of view but stars still aren't round in the corners. Note that the noise in the new version is higher than in the old version since I was in a more light polluted area tonight, so please ignore that when looking at the images.

This is the new scope:

The same image with the old scope:

Center/Corner details on the new scope:

Center/Corner details on the old scope:

What do you think? Do you think the new RedCat is good enough or should it also be adjusted?

Hi everyone,

I heard back a week ago from FLO. They sent to scope for collimation/calibration to Es Reed. Unfortunately, after inspection, it turned out to be an uncorrectable astigmatism (probably from the factory) so FLO sent me a new replacement unit that I received last week. I haven't tested the new scope yet (clouds...) but I will try to update this post with a new shot of the North America Nebula for comparison as it might be useful to others in a similar situation.

Thanks for your help everyone! Really appreciated. 👍👍

I have contacted FLO. Like @Adam J, they think it is a mis-collimation issue. Since RedCats are currently out of stock everywhere, they can't get me a replacement but offered to get it collimated again with their specialist. I think that's a fair alternative. I will keep you posted after the repair (don't know how long it will take).

Thanks again.

3 minutes ago, PadrePeace said:

Try reducing your backfocus slightly. If you can focus using the HFR in your capture software that might give you a sharper image to work with. At F4.5 your focus window will be small so do expect that when focusing. Bat masks are not the best tool with fast scopes in this range in my experience. Go for the smallest/lowest HFR reading you can get. 
It’s not too far away given some. Good luck. 

Thanks! I'll try that next time 🙂

No play but the standard M48-to-F-Mount adapter is not the best quality... So maybe it's not perfectly parallel to the back of the scope. I wonder if I should have gone with the high precision version instead.

It does have an integrated field rotator, which I used to frame the target. I would hope the rotator can be used in the field without requiring a tilt adjustment afterwards. Otherwise, that makes its pretty much unusable. 🤨

I'll contact FLO and WO directly and see what they think.

Thanks

35 minutes ago, kirkster501 said:

I was also going to suggest the focus.  I have borrowed one from a very kind forum member and I notice focus is critical and not so easy to eyeball.  If I buy one I will definitely motor focus it.

I used the included Bahtinov mask and made sure the diffraction spike was bang on in the middle so we can probably rule out focus issues

Hi all,

I had another go last night at the same target. I made sure the focus was bang on and here are the results (RAW file below). It looks a little bit better but I still see elongated stars and the corners while the center stars are round. The analysis in CCDInspector seems to confirm that.

What do you guys think? Should I send it back?

Thanks @david_taurus83! I will try again, hopefully tonight (the forecast looks promising ATM🤞) and report back.

I agree, the focus might have slipped a bit (I did use the included Bahtinov mask). However the stars at the edges look elongated in all sorts of different ways. Could it be the result of bad focusing or could there really be an issue?

1 minute ago, david_taurus83 said:

Has the camera been modified? 

No, stock DSLR. I should also mention: I don't see this issue with any of my regular photo lenses.

Hi all,

I received my RedCat 51 a few weeks ago (from FLO) and had first light this weekend. After initial post-processing it seems there might be an issue with the scope (possibly the tilt?). 

Here are one of the RAW files, the initial post-processed stack and a few measurements using CCDInspector:

Single exposure RAW:

Processed stack:

Curvature analysis:

3D Map:

What do you guys think? Should I contact FLO? Return it? Attempt adjusting the tilt myself?

Thanks in advance.

Xav''

My target was the North America Nebula (NGC7000)

Equipment used: Redcat 51, Optolong L-Pro 2", M48-to-F-Mount ring adapter, Nikon D5300

Settings: 180sec subs, ISO 1000, 50 lights, 17 darks, 16 flats, 16 bias