bottletopburly

Taking a punt on a cnc spider vane for my 200pds from AliExpress 

10 hours ago, Elp said:

Its not just that, when using Siril you actually think about each step and what to do (and see the result each step and rectify along the way if needed), with DSS it's pretty much load and go, I still use it but usually if I just want a quick stack to look at.

Yes I think your right just need to get my head around manually using it rather than script’s, always  found it a bit confusing and remembering workflow, I must give another go .

1 hour ago, michael8554 said:

Lots of spec, but no image or link to a problem Flat ! 

Michael

I will dig those out 👍

Using my 200pds i have had issues with flats in dss  or so i thought but i ran same files in Astap and Siril (pre processing script ) and flats work fine ,dust bunnies removed anyone any idea why DSS  flats not working ,Darks ,Dark flats and Flats used ,i use a EL panel as light scource ,1 sec flats  histogram approx one third ,1.2 sec flats give an ADU of 25000 using a zwo533mc ,ir blcking filter ,i tried various alogorithms in DSS to no avail ,asap normalizes the flat to compensate for colour shift if a white scource not used and i would say the El panel is not a true white scource  other than that i cant see why dss fails to correct , using my 70 mm refractor and an ipad as light scource flats are fine in Dss if my memory serves me correctly .

6 minutes ago, SAW said:

I'll be using my ZWO EAF on it.

Have a look https://www.eastmidlandsstargazers.org.uk/topic/22462-new-focuser-on-the-mn190-woop/

I upgraded my 200pds to a baader Steeltrack much better not that you need to change straight away 

No corrector required for MN, though both need a decent focuser I know someone on the east midlands forum that just upgraded the focuser body (AliExpress I think )only on his and turned out a decent focuser good stars 

49 minutes ago, Gasman said:

I don't think sick in the gears would help with slewing 😂.

Steve

Meant stick 😂

Used RVO for doing a belt mod a few years ago can’t recommend I’m afraid , shoddy springs to mind , won’t mention the sick they left in the gears .

Saw a post on APT discord server regarding Gso RC scope and a known light leak and the remedy to fix it also affects rebranded Gso scopes may be of use to some 

https://www.thingiverse.com/thing:5174299

https://www.astrobin.com/forum/c/astrophotography/equipment/rc6-r8-r10-baffle-extension-model-ready-to-be-3d-printed/

I use a L Extreme with mine though I wouldn’t recommend, I believe askar do a duoband of similar spec slightly cheaper and doesn’t I believe suffer from halos on bright stars other be I use is a Uv/ir  filter 

Zwo 533mc Gain 100 (unity) offset 20 , -10 ,Darks and flat darks library, usually 180 sec exposures sometimes shorter depending on target .

Are you getting light leaks into your calibration frames ,i was and thankfully anther sgl member spotted the error and seems to have sorted once i shot new darks flats and  flats,Darks  ,i was using a newtonian though .

Wow that’s cracking 👍well done 

Maybe @han59 can help

+1 for Apt does everything I need it to do .

Have you ran eqmod setup first and set baud rate and searched for correct comm port ? Assuming you have if you can connect to mount ,  In phd 2 settings have you chosen the correct driver from the menu to connect to the mount .

 Have a look at @han59 reply in this reply regarding converting to mono in Astap may be of help 

How are you finding cooler on the 585mc 

5 hours ago, ONIKKINEN said:

Looks very clean, these should work well.

Phew 👍 thanks .

Dave 

@ONIKKINEN Currently reshooting darks /df , how do these look so far 

DF_NGC 4565_3308_Bin1x1_2s__-10C.fit DF_NGC 4565_3255_Bin1x1_1s__-10C.fit D_NGC 4565_3182_Bin1x1_120s__-10C.fit D_NGC 4565_3206_Bin1x1_180s__-10C.fit

3 minutes ago, ONIKKINEN said:

Just went trough the files, and yes you have significant light leaks that make calibration probably impossible, even with the new files.

First your old dark which is completely ruined by the rear leak, see a rainbow rendered stretch (blues are dark and reds are bright, the light leak is clearly skirting around the primary mirror from the rear of the scope):

But your new one is not great either:

Clear gradient, which shouldn't be there. Median values in the new dark are around 460 when they should be very close to the offset value of 10 which with your camera results in 400 in 16-bit values so you still have almost 60 electrons of light leak per pixel here when just one will make calibration difficult!

In short, light leaks still reign supreme and to fight that i recommend you take the camera off the scope and shoot a library of darks and darkflats in complete darkness. The light leak issue still needs to be solved because they will imprint the weird gradient onto the light frames themselves, which may result in funny looking flats calibration even if the darks were taken in darkness.

On the exposure length and histogram, i think yours are just fine. Unnecessarily long exposures though, there is no need to expose for 4 seconds with your camera but of course also no downside other than it will take a while to capture the flats.

Your flats histogram looks like this:

Mine looks like this with a triband narrowband filter:

Mine calibrate the image just fine even though 1 of the peaks is nowhere near the center. Basically dont worry about the histogram, as long as nothing is clipped to black or white you will have good flats calibration. If you want to nitpick the flat you could push the histogram a little bit further so that all the peaks are centered around the midpoint but i dont think there is a point for doing this other than peace of mind.

In short, round 2: i wouldn't worry about the histogram at all, seems good to me. I think a lot of the flats related talk found online relates specifically to older cameras that can have nonlinear sensor responses to light and/or exposure length and so need to take some specific histogram and a long enough exposure to make the flats work (294 might be one of them). For the new Sony sensors (533,571, the fullframe version + others) you just dont need to do any tricks since the sensors are 99% linear and have no weird instability issues with any exposure lengths. I take my flats at 0.05, 0.2, or 1s depending on what gain and filter i used and never had any weird calibration issues.

Thanks for looking at least i can narrow down the issues and resolve hopefully any leak issues i will shoot a dark frame/Dark flats library , i need to take camera off  scope anyway as i have an OAG to fit , the steel track cocuser may also be leaking light around drawtube entry so will investigate that too .

10 minutes ago, carastro said:

I have come across this problem before with two other new imagers using the APT flats aid and it to me doesn't appear to work properly.  APT is an excellent bit of software otherwise.

On both occasions I got the imagers to use the histogram and simply take a flat exposure without using the APT flats aid.  Make your length of sub short enough so that the histogram is about 1/3 to just under half way across.   

This has resolved the problem in both cases.

I must tell IVO (APT)  about this problem as he is very approachable.

Carole 

Thanks carole i will retry later new flats with rear ota covered and see if this solves the problem ,if not i will look at the histogram .

5 hours ago, ONIKKINEN said:

I am assuming you have taken the flats after the imaging session, without touching anything on the scope such as removing the camera etc? If so, need to do some educated guesswork. Post a flat, a light frame that matches that flat, a dark frame and a bias/darkflat frame in .fits format as an attachment so the raw data can be seen for possible clues.

I am guessing it will have something to do with light leaks if all the calibration frames are otherwise sound. The rear of the tube will let in light unless you have blocked it somehow for example.

 

hi thanks ,yes imaging train still in situ not moved , i currently have scope covered and just reshot a dark frame and i think you may be correct about light leak from rear as the darks were showing a shadow so i just went out and covered rear with a black bag and that seems to have solved the shadow mark so i have posted a light, a dark flat ,Flat from the other night camera hasnt moved ,and reshot a dark with ota covered, a dark with ota rear not covered, and a Dark flat with rear ota covered  so i need to find a suitable cover for rear of ota images from today the 9th are the reshot ones  . 

Target was the needle galaxy and the moon was bright .

D_Dark uncovered rear OTA_2903_Bin1x1_180s__-10C.fit D_New Dark covered rear ota _2907_Bin1x1_180s__-10C.fit DF_4_NGC 4565_2854_Bin1x1_4.1875s__-10C.fit DF_New dark flat covered rear ota4565_2914_Bin1x1_4.1875s__-10C.fit F_4_NGC 4565_2839_Bin1x1_4.1875s__-10C.fit L_NGC 4565_2683_Bin1x1_180s__-10C.fit

I have been trying to calibrate my images so using a zwo533mc ,200pds UV filter ,  so lights,flats and dark flats processing in deepskystacker , flats adu using flats aid in APT set to 25000 panel dimmed to get flats exposure to 4 seconds ,i have tried shorter exposures but i cant seem to get the bunnies to calibrate out ,so can anyone shed any light why this is ?

4 hours ago, ONIKKINEN said:

I used it for a while and have 2 major gripes with the design (mine was TS branded).

First is that it has issues with internal reflections if a bright star is within a few degrees just outside the field of view. See below for examples (the coma cluster one was particularly difficult to remove, almost ruined the shot):

There was another case where i was shooting a comet but cant find the data now. It was garbage so might have deleted it but it had a reflection across the center of the image from Pollux a couple of degrees outside the FOV.

The second is that it doesn't do a very good job as a coma corrector. Never saw good sharpness across the frame no matter how much backfocus searching i tried. In order to get decent stars across the entire frame i had to focus using a star in the outer third of the field of view. That is obviously a compromise as it means the center stars are not at their best focus. To be fair it wasn't awful, but still there are better options at similar prices (such as the 1.0x GPU) so lets say i do not recommend this one.

I upgraded to a TeleVue Paracorr and yes i know its literally twice the price so not a fair comparison but my star sizes measured in arc seconds improved by 20-30% compared to the Maxfield. On axis performance improved even more, but since i still need to focus with a non-center star the center sharpness has limited benefits.

 

***Forgot to mention that my scope is an f/4.4 one, i have seen mentions online that the corrector does a much better job for f/5 primary mirrors. Apparently something to do with spherical aberrations being introduced with faster mirrors.

Thanks for that , intresting