Evoguide50 with SW Flattener on Astrokraken rig

[vineyard]

Hello,

I took out my new EvoFlattener for a spin on the Evoguide50 earlier this week.  Ever since I got a 2nd hand Evo50 last year I've been tempted to try wide-field AP on it.  At that time, Starizona were the only ones doing it so I put myself on the back-order queue.  But it still showed no signs of shipping, so when SW released one, I switched (the SW one is also a doublet ED w FPL53 elements apparently, and is cheaper - and available - than Starizona).

The photos below show it next to a hosepipe attachment for scale, and then attached to the Evo50 and an ASI294MCPro.  I'd got the mount 3D printed by Philippe at Astrokraken.  He'd actually made it for the Starizona measurements, but as you can see it fits the SW one as well.

Attaching it is very straightfwd - basically thread off the original camera receptacle, and thread the flattener on.  And then thread the camera on - it needs 17.5mm back focus.

My only go-to mount is an HEQ5Pro, so it was definitely overmounted!  But it still need balancing for weight.  The HEQ5Pro weights were too heavy though - luckily I had an iOptron SkyGuider Pro weight which fit, and which balanced it perfectly.  That's a good sign since it means it would work in the field on that.

One mistake I made once mounted was that I tightened the camera holder ring snugly before I focused.  So when I was looking at EKOS focus module and turning the helical, there was no change in star image.  Then I realised what I'd done, loosened the screw on the camera ring, found focus and then tightened it back again.  Finding focus was v easy b/c Philippe includes a bahtinov mask - my first time using one, and so much easier.

A couple of wrinkles I've noticed on first use - fixable in different ways I suspect.

1.  There's no easy way of putting a LP filter on.  There are threads on the front of the Evo, but they are too big to directly attach a 2" filter.  They'd need adapter rings which I guess you can get made from a camera shop?  This would make the aperture slightly smaller though.

Alternatively, you could use a 1.25" filter on a nose attached to the camera, but then the camera won't be able to thread on, and you have to use the three placement rings to hold it, which I don't like the idea of for stray light entry.  I may be missing an obvious fix to that w a different type of adapter.

[EDIT 2: there does seem to be a way if you have a ZWO camera.  Using this which I believe comes as standard w some cameras - thread the filter into that, and then thread that into the camera, and then thread the remaining T2 threads onto the flattener.  I tried that today and was still able to find focus on v distant terrestrial objects so hopefully that will also be the case w stars - in which case, great!]

2.  There is vignetting, at least w an APS-C size chip like the ASI294 has.  I suspect it may be caused by the front edge of the helical focuser in the Evo?  I guess you could crop the image, or alternatively use a smaller chip size - or, if using a front-mounted filter, maybe the smaller aperture will also kill the vignetting.

[EDIT: another possible thing might be to take a bit off the front of the helical...]

There is a test image below of M31 to show the flatness.  Nothing done to it other than DBE in PI.  There is still some curvature in the top right corner (and I think also a bit in the bottom left).  @vlaivalso noticed some slight astigmatism in the corners, in this interesting detour that happened when I first tried to use DSS to stack.  It looks like the edge effects caused by the vignetting, combined w DSS quirks, can lead to weird "halos" in the overall image shape - these are much less present if stacked in PI (a tip from Vlaiv!).  I'll play with this image a bit more to see if those weird halo gradients disappear in processing.  Else it's probably better to use a slightly smaller chip?

I also grabbed an hour on each of the Perseus Double Cluster & M45 so I will play with those to see what PI-stacked and PI-processed images come out like.  Will post them in the Imaging forum.  If they come out ok, then this is a nice little wide-field AP set up that can be put on a SkyGuiderPro type of mount - and is a lot cheaper than a Redcat!

Cheers,

Vin

Edited October 14, 2020 by vineyard
added [EDIT 2: ] section on a way of adding a filter

[ElwoodBlues]

I use the evo has a guide scope and I'm in the process of putting this together myself for a widefield setup, just waiting for clear nights.

I have been using that adaptor you linked for filters on my 294 without issues.

I was kind of hoping I wouldn't get vignetting, but looks manageable.

Being relatively new to this hobby,I was more concerned about the image scale at 3.95pixels ,seems to go against all my research so far but I see some fantastic images at this scale and higher.

Hopefully I get outside soon and see how this goes. All part of the fun 👍

 

[vineyard]

On 14/10/2020 at 22:19, ElwoodBlues said:

I use the evo has a guide scope and I'm in the process of putting this together myself for a widefield setup, just waiting for clear nights.

I have been using that adaptor you linked for filters on my 294 without issues.

I was kind of hoping I wouldn't get vignetting, but looks manageable.

Being relatively new to this hobby,I was more concerned about the image scale at 3.95pixels ,seems to go against all my research so far but I see some fantastic images at this scale and higher.

Hopefully I get outside soon and see how this goes. All part of the fun 👍

 

Sorry for some strange reason I only just saw this almost 4 months later.  Hope it went well for you!

[Neko]

Looks rather promising! The M31 looks great

although the 294 camera is not APS-C , but rather 4/3" chip... according to the specs, it chould deliver

a flat 28mm image circle, that should be enough for APS-C , an it should be more than enough for a 4/3" 

like the asi294mm/mc pro, so maybe is the distance with the camera?  back focus for the flattener is

17.5mm , exactly the same as the ZWO cameras.. could it be some sort tilt? 

try checking the images in ASTAP or CCD inspector maybe? 

Still, very good result   

[vineyard]

Thanks @Neko yes you're quite right its 4/3 not APS-C, not sure how I confused that, doh!

That's a good idea re tilt - I ran it through ASTAP/CCDinspector and it looks like there is some (see screengrab).  Not sure if that might be causing some of the DSS stacking artefacts too?

I do have a tilter that I should fit in the train (its 11mm optical path which is exactly the length of the nose on the 294).  Will try that next time there's an oppty to set it up for a proper imaging session - its been so miserable or so intermittent for so long now.

Cheers & stay safe.

 

[Neko]

40 minutes ago, vineyard said:

Thanks @Neko yes you're quite right its 4/3 not APS-C, not sure how I confused that, doh!

That's a good idea re tilt - I ran it through ASTAP/CCDinspector and it looks like there is some (see screengrab).  Not sure if that might be causing some of the DSS stacking artefacts too?

I do have a tilter that I should fit in the train (its 11mm optical path which is exactly the length of the nose on the 294).  Will try that next time there's an oppty to set it up for a proper imaging session - its been so miserable or so intermittent for so long now.

Cheers & stay safe.

 

It could be that! In my Borg 89ED with Hotech SCA flattener I was getting trailed stars by the edges with the qhy8L.. and this flattener

is more than enough for APS-C .. SO I ran it through ASTAP-CCDinspector and found out it was tilted. In  my case I think is both the CCD sensor not being

orthogonal and the fact that the image train is not all threaded like yours but rather with the SCA self centering (...yeah right  not so efective really ) and had to play with the 3 screws on my focuser to try to center it. 

Here too been very bad weather so couldn't check it properly. I tried to center it indoors by taking flats on a wall during the day, taking pics on preview/loop mode, then moving the histogram to see the vigneting circle and trying to center than in the image by moving the 3screws similar to a tilter would do . Not sure if that worked but doesn'seem as bad as before! 

 

Regards!

Carles

 

Edited February 18, 2021 by Neko

[Robindonne]

Ed Ting has an item on yt about this. 

[Neko]

58 minutes ago, Robindonne said:

Ed Ting has an item on yt about this. 

about the tilt? I don't know Ed Ting ^^;   could you post the link to that video ? 

Cheers

[Robindonne]

Oh the tilting I don’t know.  Sorry.  Watched it partly 

Edited February 18, 2021 by Robindonne

[Neko]

thanks!  will check it straight away! Haven't found many reviews about the evoguide50ED

 

[ElwoodBlues]

Here's a few efforts with the sw50ed and f/f .

i have only recently started imaging  using a 6 SCT  on a heq5 pro so this is my cheap way into a widefield refractor

until my bank balance and stock levels increase.

 

 

orion with the asi294mc and l-enhance filter.

40 mins total on this at unity gain .

[ElwoodBlues]

90 mins total on this. asi 294mc unity gain, l enhance filter. oh and im using startools to process.

[ElwoodBlues]

asi 294mc unity gain l enhance  2hrs total on this. Im actually using the 6se has a guide scope while i use the sw50ed for imaging🤫

 

[ElwoodBlues]

asi 294mc unity gain  15s exp   49min total. 

[ElwoodBlues]

[Neko]

@ElwoodBlues Looks great! 

is that the full frame or did you crop?  

How did you processed it in StarTools?  I processed once a pic from a friend of mine who has the L-enhance too (I only have L-pro for now.. ) and I tried it both straight from "open" and "Compose". Compose delivers better result IMHO. Since You can split the OII+Hb and Ha  then merge them as HOO 

 

[Jonny_H]

I have recently purchased Philippes Astro Kraken 50ed mount (waiting for it to arrive).

Currently using the 50ed as a guide for my 150PDS but going to start using the 50ed as an imaging scope for those larger targets (I have the f/f already).

I figured it was Best to use what I already have rather than spending ludicrous amounts of money on another scope. Although i am fully aware that spending all of your money on this hobby is the key to success.....🤔 😜

[ElwoodBlues]

2 hours ago, Neko said:

@ElwoodBlues Looks great! 

is that the full frame or did you crop?  

How did you processed it in StarTools?  I processed once a pic from a friend of mine who has the L-enhance too (I only have L-pro for now.. ) and I tried it both straight from "open" and "Compose". Compose delivers better result IMHO. Since You can split the OII+Hb and Ha  then merge them as HOO 

 

Andromeda and The heart nebula processed through standard open method.

Orion and Rosette processed with the compose module in startools . I followed a workflow from the startools forum to try and Process HOO . Unfortunately I'm still learning so unsure of the results. All images just had a small crop for stacking artifacts has i recall.

I see some images from L enhance in a fake SHO but I don't know how they do that.

[ElwoodBlues]

This is how I mounted my sw50ed on my 6 sct. I just switch cameras dependant on the scope I'm imaging with.

 

[happy-kat]

You could use compose and select to open your stacked file into say the red channel and then save that. Repeat for green then again for blue.

To then process use compose and build your image loading each split channel as you want.

[Corruptedbuffer]

On 21/02/2021 at 16:30, ElwoodBlues said:

This is how I mounted my sw50ed on my 6 sct. I just switch cameras dependant on the scope I'm imaging with.

 

Sorry for being a tad late to the party, but I just stumbled on this.  This is exactly what I'm trying to do, only I have a Celestron 5SE instead of a 6SE.  Could you share how you have the Evoguide attached to the Celestron?  I haven't been able to find anything online that seems secure/stable enough to hold the Evoguide (it's not exactly light, especially with the dovetail attached).  Thanks!