Aramcheck

Apologies for the delay in replying Mark - we were in (dark-ish) Wales last week & I had no access to my SGL log-in. I can only speak about imaging... for me the most annoying thing was the flaring around bright stars, so I'd say the primary mirror aperture ring would be my biggest return on effort. You can buy a ring, get one 3D printed, or make one from a sheet of plastic (provided you're not going to be using the scope for Solar). It's worth using a piece of tape to mark the position of the primary mirror cell on the outside of the OTA, so that when you re-insert the cell back into the OTA you can get it in the same position. You will still need to recollimate, but it shouldn't be too far out. I found it useful when collimating to have the location of the 3 mirror clips marked on the aperture ring with a small bit of white electrical tape, as you'll no longer be able to see the clips once the aparture mask is fitted. When fitting the ring, the screws holding the primary mirror should only be tight enough to hold it in place, but you should still be able to just about rotate the mirror in the cell with your fingers. (Search on the SGL for this & any mods you decide to do!) If you're also worried about hanging a camera (or eyepiece) by the two bolts found on the Skywatcher focus tube, the Astro-essentials compression ring will buy piece of mind & also centre the camera more accurately. (It also won't scratch your eyepieces) The first one I got didn't fit properly due to slack manufacturing tolerances, but FLO's customer service was brilliant (as usual) & they soon got me a replacement. One other piece of advice is to only do one modification at a time, that way if something goes pear-shaped, it'll be easier to diagnose & fix! Cheers Ivor

I've made several modifications to my 200 pds:- Sub-aperture mask fitted over the primary mirror clips, to reduce the flaring of bright stars Replacing the primary mirror springs Repositioning the primary mirror centre spot (mine was 3mm out of position) Flocking OTA + painting the edges/rear of the mirrors with black paint Astro-Essentials Compression Ring Adapter on focus tube / followed later by replacing the focus tube with a Baader Diamond Steeltrack Replacing the spider with one of the Backyard Universe type. This makes the diffraction spikes sharper, but increased the amount of light that is diffracted, so fainter magnitude stars also appear with spikes... Not forgetting the black shower cap fitted over the bottom of the scope to reduce light leakage through the gaps around the primary Light pollution / Dew shield made from a black foam camping mat. I've also switched from using the suppied Finderscope as a guider, to an OAG. The only modification I've undone was using silicone sealant to hold the primary, as I ended up with the mirror being pinched & horrible stars... Took ages to figure that was the problem too! The scope came with a couple of extension tubes for visual, but only use the 200pds for imaging & have a second hand 200 dobsonian for visual (that was free)! Recent image of NGC2805 below... Cheers Ivor

In Pixinsight, if the satellite trails persist then you can increase the rejection setting. Alternatively, you can force rejection by drawing a black line over each trail in the subs. (I use a bit of javascript which I found on the Pixinsight forum, entering the start/end co-ordinates + line width). Cheers Ivor

After my old PC hard-disk died I got an AMD Ryzen 7 5700G with Radeon Graphics system from PC Specialist. It's got a couple of SSD drives & two regular hard discs & 128 GB Ram. Running Windows 11 & all processing done with Pixinsight. The SSD drives & extra memory really made a big difference to processing speed. Cheers Ivor

Astrobloke shows how to record the PPEC on his youtube video: https://youtu.be/PfvWhx7ozi0?si=7EEuao1nvAxTY1Ni&t=942 I've only tried it couple of times & didn't see any noticeable benefit, but that could be down to other factors in my mount... Cheers Ivor

Not sure if this will be eligible - please ignore if it's not! From the 14th Jan 2024, minor/dwarf planet (4) Vesta appeared about 1/2 deg away from M1-Crab nebula, so I got 120 x 60s subs, inbetween other on-going projects. During processing I discovered that there was also another much smaller asteroid (4299 WIYN) in the data, which was a neat coincidence. Captured with SW 200p-ds, ZWO ASI 2600 MC-PRO & AZEQ6-GT-Pro with OAG + ZWO120mm guide, using APT+PHD2. Processed in Pixinsight. Bortle 7/8 skies from light polluted Leeds. Because Vesta was very bright & had prominent difraction spikes, I used the linear data to superimpose Vesta onto the main image... 4299 WIYN however was very faint, so I did a separate 'comet-aligned' stack to get an image of the asteroid; and then used Pixel math to create a set of asteroid-only subs using the PSF centroids for rough alignment... However because PixelMath only works at a pixel level (doh!) I then had to do a dynamic alignment back to the original sub-frames to correct the asteroid position. The main reason for picking this target was that my wife has a bit of meterorite which is a said to have come from Vesta... I didn't think it would take so long to process though! Cheers Ivor

@Captain Scarlet - That's very generous Magnus - I'll send you a message. Many thanks Ivor

I don't suppose anyone knows where I can get a replacement spring for my AZ-EQ6 GT Pro? I accidentally loosened the saddle too much last Friday night when setting up & one of the springs that goes over the bolts fell off & made a run for it... I've searched the garden, but I'm afraid it's gone for good. The spring is approx: 30mm long Outside Dia approx 10.5mm Inside Dia approx 8.5mm Wire approx 1mm 11-12 loops I tried buying some from a well-known retailer, but they are much stiffer so I don't want to risk using it in case it strips the thread on the mount. Many thanks! Ivor

This was a bit of a filler target in between other objects over four nights (29/09 + 13/14 & 16/10/2023). Total 138 x 3min subs (weighted exposure time 5hr 13min), with SW200pds + ZWO 2600MCPro, with OAG/ZWO120mini & AZEQ6-GTpro, from Bortle 7/8 back yard in Leeds. Cheers Ivor

Here's the comet from the 14th Oct (last Saturday). 42 x 3min exposures with Skywatcher 200pds & ZWO ASI 2600MCPro, from our Bortle 7/8 back yard in Leeds. Over the 2 hrs 14 min session it moved approx 71 arc seconds. Not that happy with the processing, but I look forward to trying it again next year (fingers crossed). Cheers Ivor

@Zermelo I don't suppose you've got a source website for that graphic? Cheers Ivor

This is the result of 3 x 1hr sessions last month with the Optolong L'extreme filter (during the M57 sessions after the ring had fallen behind trees) plus an hour of RGB data (from 12 Sept.) for the stars. SW 200pds + AZEQ6 GT-PRO, ZWO ASI 2600MCPRO + OAG with ZWO 120mm... Bortle 7/8 Cheers Ivor

A combination of 463 x 3 min exposures with the L'extreme dual narrowband Ha/Oiii filter (23 hr 9 min) from 7 nights - 20/08 to 07/09/2023; plus 96 x 3min regular RGB subs (06 & 08/08/2023) + 101 x 3min regular RGB (05 &12/08/2022)... I was trying to see if I could get the faint outer shells which J.C. Duncan discovered in 1935. Last year I got the barest hint of the first outer shell & as the RGB this year looked promising I decided to switch to the dual narrowband filter & combine data sets. Processing the luminance was a challenge due to the M57's high dynamic range between the bright core & the very faint outer shells; and combining the RGB stars & nebula core with the narrowband outer shell was a bit of a fudge (to say the least). SW 200pds + AZEQ6 GT-PRO, ZWO ASI 2600MCPRO + OAG with ZWO 120mm... Bortle 7/8 Cheers Ivor

Back in April / May I collected data on NGC3718 & was drawn to an arc-shaped smudge at approx: RA 11hr 30m 24.544s - Dec +52 48 29.81. (Top right / inset in image). I've been unable to find out what the object is from looking at Simbad/Aladin & with Pixinsight's AnnotateImage script. Does anybody know what it is? I've stacked 24hr 12m (494 x 3 min) captured over 12 nights, before I'd worked out that my primary mirror was pinched, so please ignore the star tails... Also my processing is somewhat heavy handed & has pushed the data too far. I'm hoping to get more data next season to improve the fainter regions in NGC3718 & solve the star tails. Also highlighted in the top/left inset is quasar SDSS J113206.13 +533808.3, which is something like 12.6 billion light years away... it's one of several which was picked up by Pixinsight's AnnotateImage script. Image taken with SW200pds with ZWO2600MC Pro, OAG with ZWO120mm, SW AZEQ6-GT Pro mount. Bortle 7-8 skies... I'm not sure if the smudge is a distant interacting galaxies, a case of gravitational lensing, or just a nebulous region. It's there on Aladin/Simbad... Any ideas on what it is much appreciated! Cheers Ivor

@StarDuke82 What's the advantage to rotating the supression pads? I use them but have never paid any attention to their orientation in relation to the scope legs. Many thanks Ivor

@edarter Yes - I used the image solved co-ordinates from the 2022 session and a framing mask in Astro Photography Tool to make sure they were the same orientation. What I didn't bargain for was that I'd had to rotate the OTA in the tube rings when I fitted an OAG... so the diffraction spikes were in different orientations between sessions. I made a mask of the pre-nova spikes from a copy of the Combined non-linear image & then substituted the pixel values from the post-nova image, and again used a curves adjustment to hide the joins. If you look at the bright stars in the combined image (attached) the additional spikes have been removed reasonably well. You can still try to incorporate data with vastly diffferent orientations by using the NormaliseScaleGradient script (in Script->Batch Processing menu). I've used that in the past to avoid the sharp changes in background sky values with data with different orientations. (I have the paid version of NormaliseScaleGradient). Cheers Ivor

With my 2022 & 2023 data I stacked the pre/post nova images separately & also as a combined set to maximise the signal to noise ratio. In Pixinsight I used LinearFit to make the sky background the same & applied the same stretch to each of the three masters. I then made a mask of the supernova & used Pixelmath on copies the combined image to replace the pixels with a) the pre nova data & b) the post nova data. A slight curve adjustment was also needed hide the join... Results looked ok, but when I later made a GIF (which only has 256 levels) the join is still a bit visible... Cheers Ivor

Something I'd forgot about, which I think is worth mentioning, is that (at least in my experience) when with the camera at focus the crayford drawtube protudes into the OTA. It's nowhere near as bad as the 130pds, and you'll find examples on the SGL of people shortening it. (BTW the Baader Steeltrack doesn't exhibit this problem) Cheers Ivor

Not all of the pictures are mine - you have to look at the "Notes" for the acquisition details. The planetary images are all by other LAS members / different kit. About 9 months ago I changed the focuser because I suspected I was getting some tilt. With an OAG & the ZWO 2600 MC-PRO the camera setup is just over 1kg, so swaping the focuser was more for peace of mind than anything else. Another option would have been to remove the rubber spacers in the Crayford (as mentioned in some SGL threads), but I didn't feel confident doing that... Fitting & aligning the Baader steeltrack wasn't easy and required some added foam/sticky tape to reduce light leaks (again as per SGL threads). If sticking with the Crayford I'd recommend fitting a compression ring adapter to hold the camera more securely! At first I didn't have a guidescope & then started using a converted SW 9x50 finderscope with an adapter to fit a ZWO120MM... More recently I've swapped to an OAG to help eliminate any problems with differential flexure. I've also started using a ZWO filter drawer, which seems to work ok, although I've found that swapping between a IDAS LPS-P3 and an Optolong L-eXtreme requires refocusing. (I found out the hard way that with the L-eXtreme positioned in front of the OAG I couldn't get sufficiently bright stars to guide with, so using a filter drawer next to the camera means I don't have to dissasemble the optical train (camera/filter/spacer/oag/coma corrector) when changing the filter...) The Player One camera looks good! Cheers Ivor

I've used it for about 3+ years with a Baader MKIII coma corrector, initialy with a Canon 600D (astromodified) and more recently with a ZWO 2600 MC-PRO. (Many images taken with it here: https://www.astronomyleeds.org.uk/gal/gallery.html ) I'm happy with it, though I've done various mods - flocked the OTA; replaced the focuser with a Baader Steeltrack; fitted a primary aperture mask; replaced the primary clips/springs as suggested on the SGL; and painted the secondary rear/sides matt black. The only other scope I've used is a 130pds, but I prefer to use the 200pds unless it's too windy. Cheers Ivor

I had a quick play with the data... Rough process notes in the attached text file. The GAME script can be found here: http://www.skypixels.at/pixinsight_scripts.html and the EZ Processing suite repository is here: https://darkarchon.internet-box.ch:8443/ I'd recommend the Russ Croman's Xterminator plugins, but if not using them do the deconvolution in place of BlurXterminator on the luminance & not the RGB. Similarly substitute conventional noise reduction techniques & either don't bother removing stars, or use the free StarNet2. I'm still trying to get a workflow I'm happy with using the new Xterminator tools, so the attached is a work in progress... Different images will need slightly different approaches I find. Cheers Ivor PS: You may get a better result by stacking in Pixinsight rather than DSS. PI will give you a 32 bit starting point & I expect it's rejection algorithms to be better... M101 - SGL process.txt

Mod's - please remove if deemed inappropriate... In anticipation of a review of national planning policy in the UK, CPRE have launched a petition calling for stronger national and local policy to combat light pollution. Using a pro-forma email their asking people to write to their MP about the issue. If interested - simply use the link below:- https://takeaction.cpre.org.uk/page/119341/action/1 It only takes a couple of minutes at most. Cheers Ivor

In your image you also got the much fainter outer HII region, which is the kind of thing I always struggle with. It also shows what looks like a larger second outer bubble around the O5 star BD+50 866. Cheers Ivor

@labtech1122 - The stars are a bit out of focus & I think the elongation at the edge is due to the camera back focus being too large (i.e. camera sensor is too far from the field flattener). The blue rings look to me like internal reflections from the bright star. Just my 2p! Cheers Ivor

NGC1491 in Perseus from 13/14 Feb. (SW 200pds + ZWO2600MCPro + AZEQ6 with OAG & ZWO 120mm + Bortle 7/8 sky). 60 x 1min exposures for the stars with IDAS LP3 light pollution filter & approx 146 x 3min exposures with the Optolong L'Extreme dual narrowband filter. This was my first attempt with the L'Extreme so on the first night the subs were a bit out of focus as I simply switched from the IDAS after the first hour, without refocusing. The screengrab of the unprocessed data (with just an autostretch) shows what a difference the L'Extreme makes & also the advantage of additional exposure time... Cheers Ivor