Single sub of M31 wih StellaLyra 6" f/4 + SW 0.9 ComaCorrector + Canon 5D MkII full-frame

[Rallemikken]

As the topic says, this is a single sub under bortle 4 skies at 60 seconds at ISO 800. Conditions average, some haze, but this post is meant to show how this CC works with this scope and a fullframe. I ordered my SL 150mm from FLO with the Baader CC, but due to delivery problems had to settle with the slightly cheaper 0.9 reducer/coma corrector from SkyWatcher. As Astrobiscuit says, the proof is in the pudding: I'm not disappointed. Slightly distorted stars at the far out corners, but this sub is shoot with a Canon 5D MkII fullframe. And to be clear: Don't stack subs with this combo without good flats. And with "good flats" I mean flats shoot against a blue sky, but with the rig safely placed within the shadows.

A good estimate of what this combo can do. Scope is right out of the box, no mods except a black stringbag around the bottom to keep my dew heater.

Edited October 22, 2022 by Rallemikken

[Keltoi]

have you tried fitting an EAF to this scope at all? if so which model and how did you manage with it?

[pipnina]

That's pretty good!

I wasn't aware full frame sensors could work on these newts- my APS-C sensor already had 33% vignette on the TS-GPU corrector and 25% on the MPCC MKIII

What does a flat here look like, out of interest?

[Rallemikken]

On 26/10/2022 at 00:40, Keltoi said:

EAF

Sorry for late reply. No. I image with two newt's, this StellaLyra and a SkyWatcher 200PDS. I only use Canon DSLR's, and they are very simple to focuscheck agains Vega on session startup. And I very seldom have to fiddle with the focus wheel once it's set. Both these scopes keeps focus very vell.

[Rallemikken]

On 26/10/2022 at 00:45, pipnina said:

What does a flat here look like, out of interest?

Sorry for late reply. Brutally compressed, but the real thing. Single flat shot at 1/640 sec @ ISO 100. This library contains 50 flats. As you can see, even and nice. They tend to be a little darker on the side that correspond with the bottom of the camera. You can see it in this one too.  I always take my flats against clear skies. With newt's, dust bunnies is never a problem, and as long as I keep the coma corrector clean I can use my library of flats for months.

Edited November 27, 2022 by Rallemikken

[tomato]

Apart from the darkening along the bottom there isn’t much for the flat to correct looking at that image. How do you keep your sensor window free of dust?

[ONIKKINEN]

2 hours ago, tomato said:

Apart from the darkening along the bottom there isn’t much for the flat to correct looking at that image. How do you keep your sensor window free of dust?

Canon cameras clean their sensor automatically each time you power off, so there may not be any dust. Not sure i ever saw dust on my 550D actually now that i think about it.

[AstroMuni]

On 21/10/2022 at 21:44, Rallemikken said:

A good estimate of what this combo can do. Scope is right out of the box, no mods except a black stringbag around the bottom to keep my dew heater.

I was keen on buying this and then I saw posts about how much the drawtube needs to stick out in order to get focus etc. How far out is it in reality? Pictures would also help please.

[Rallemikken]

31 minutes ago, AstroMuni said:

How far out is it in reality?

Pictures not necessary. The focuser has markings. With my Canon 5D MkII and the SW 0.9 CC I get focus at 34mm. If I swap my 5D for my 600D I still have focus, only minor finetuning requiered. Without the comacorrector I have focus slightly over 40mm (42-45?), don't remember 100%. At 34mm the drawtube is well up in the focuser. I recon it will be flush at 28-30mm. Fully down it will stick out the same amount. Without any additional optics you can get focus with these Canon cameras and still have appr. 10mm inward travel left until it is flush.

[Rallemikken]

3 hours ago, tomato said:

How do you keep your sensor window free of dust?

Clean air. Live in Norway. Season does not start until mid-september, and there's neither bugs or pollen in the air. And it's cold. And I try to balance my scope in a way that keep the camera on top, or at least with some downhill from the sensor. Let gravity help as much as possible. If I can, I avoid any glass between the secondary mirror and the sensor. Gives the sharpest images, without faults of unknown origin. But at f/4 it's hard to do without any correction, and the SW 0.9 CC does a decent job. Have had to take it out only a couple of times, with megabright stars in the frame.