Ken Mitchell

Thank you! 🙏

Update: So I recently purchased the Explore Scientific x3 focal extender. Done some tests with it and must say I'm very pleased with its performance. My biggest concerns were softness and vignette in the corners but I can't see any of those in the images I took. Here are some examples taken with the barlow+72mm apo and zwo asi120mcs Ken Moon mosaic from 07/13/2020 Moon mosaic from 07/26/2020 Jupiter 07/14/2020 Saturn 07/14/2020 Venus 10/07/2020 Mars 07/19/2020

Just finished 2 days imaging at Cygnus. Always wanted to do a widefield of the N-America and Butterfly nebula. Decided to do a two panel mosaic, nothing fancy, so one target/night. Managed to do 4 hrs each night, which should be enough to get decent amount of detail. The first time I'm trying this region with a modded dslr, had good hopes after seeing some of the results from other members Although at first sight I was a bit disappointed. The original stack didn't show too much data but after doing some stretching a lot of the Ha nebula showed up. The more I processed the image the more 'hidden treasures' were revealed. The most difficult part was the blending, as I decided to do 2 panels and wanted to get as much sky in the image, I only had an overlap of maybe 15%. So blending both with a lens that suffers from 'minor' coma this was a challenge. A zoom into the image reveals some areas where I did the stitching and blending, just look the other way and no one will notice 🙃 Here are some of the details on the image and equipment: Nikon d90(mod) Nikkor 80-200mm f2.8 settings: 125mm, f4, iso400 2 panels of 4hrs each, 300 seconds subs guiding: ZWO asi120mcs TS 50mm guidescope Tracking: Skywatcher Star Adventurer software: guiding: phd2 Stacking: Deepskystacker 4.2.2 Processing: Adobe Photoshop Ken

4 days of active region AR12767 Ken

Got a clear day today. Comparison of AR12767 from 07/22/2020(left) and 07/24/2020(right) Sunspot looks stable, not much difference between the two days. Umbra seems to have increased slightly though. Ken

Was hoping to do a new session today to do a comparison, guess what ... ☁️☁️☁️ Ken

For solar enthusiasts, a new active region is facing Earth, AR12767 with HSX classification (McIntosh classification). Here is an image of it I shot in false color on 07/22/2020 Equipment: ZWO asi120mcs, TS72f6, ESx3 focal extender, Baader solar film nd5, SWSA Ken

Been doing a bit of planetary work with the SA lately. Got my first 'decent' image of Venus, Jupiter and Saturn a week ago. This hobby is so addictive I immediately bought the x3 Explore Scientific 1.25" focal extender. After reading nothing but positive comments on the optics I was thrilled to give it a go myself. My goal was to do a mosaic of the Moon. The first opportunity I got, which was 8 am during sunrise, I got out and started imaging. What a great feeling seeing the Moon so close! It felt like 30 years ago, a 10 year old kid looking for the first time through a telescope at the Moon. Can't wait to explore those craters and Moon features a bit more. I took about 30 panels, to make sure I had every part of it. Sessions of 100 frames each, stacked in AS3! and run some wavelets in Registax. The files were imported in Photoshop, aligned and blended using auto panorama mode. Removed some of the missing frames in the background and did some pp in adobe raw. Camera: zwo asi120 mcs Optics: TS72 refractor with ff ES focal extender x3 Captured with ASIcap Ken

Ciarán, The different exposures were planned for 2 reasons. First, as you mentioned, I wanted to make sure having enough short exposures/data to get as much detail in the core and surroundings. Second, this was taken in the morning so as the minutes passed the sky becomes brighter and the comet will get lost in the background. So shorter exposure will compensate for the background brightness and at the same time get the detail for the core. I started with a 30 second frame session and reduced the exposure with 5 seconds every 20 frames or so. Hope that makes sense. Ken

Here is a new edit using the comet stacking mode and the DSS stacking settings for the lights on average to get the most startrails in the final. By looking at the startrails it seems there was some vibration in certain shots. I tried to do the same post processing on this image as the original one, it's close but not a perfect match. I like both images but personally prefer the one with the starfield. Ken

Thanks, I've thought about experimenting with these settings. I'll give it a go 👍 I just want to show you the results of the mixed stacking by DSS. No color and full of banding, no idea why it turned up like this. I believe the blending algorithm in DSS is just bad. No idea if different stacking settings would give better results. Ken

This is a single uncropped 20sec SOOC sub for size reference. Ken

Thanks! Very little cropping, I just cropped the stacking artifacts on the edges. Ken

First attempt and first clear morning after 2 weeks of bad astrophotography weather. Taken about 2 hrs before sunrise on 07/13/2020 The image still has some startrails from the comet stacking mode in DSS. I've used the comet stacking mode and normal stacking mode and blended both together in Photoshop to get the comet with its starfield rather than startrails. Difficult process to do this manually. If someone knows a method/software that does comet stacking with its starfield, please let me know. DSS failed me on several occasions using comet+star stacking method. Ken Equipment and image detail: Nikon d610 TS72 APO + TS72flat settings: 432mm, f6, iso400, 40min. Different exposures ranging from 30 sec to 5 sec. Tracking: Skywatcher Star Adventurer software: Stacking: Deepskystacker 4.2.2 Processing: Adobe Photoshop

Hi Alan, Sry for the late reply, About my setup, it is almost identical to yours, from what I see in your post. Guidescope is also on ballhead. For polar alignment, at first I put Polaris more or less at the right spot. Then I start to locate the target, once it is centered I adjust the polar alignment and do a calibration in phd2 and start the guiding. I start my exposures and look at the graph in phd2, in particular the red dec line. The better your PA the longer the red line will stay in the middle. If it drops or rises too fast I make small adjustments to the PA If it stays in the middle for about 10 minutes I know the PA is pretty good. If it drops or rises too fast you will have much more drift and it will be visible in your stack(edges). It doesn't really affect your guiding. Ken

Thanks! 240sec subs. This is a single sub cropped. Stars are still a bit bloated because of the mod and I don't use any uv filters. Ken

Thanks! I had a good PA, subs were very good at 240sec. Guiding was around 2", pretty good for the SA I've been doing some 'experiments' with phd2 to refine PA on the SA. As it doesn't guide in Dec there is usually some drift and the graph won't stay in the middle. This can be used to perfect your PA. When the red dec line falls to the bottom of the graph it means Polaris is too high on the polar scope hour circle. When it drifts to the top, Polaris is too low. From there on you can do some fine adjustments. Usually the red dec line disappears from the screen after +-10 (in my previous sessions) now it stayed in the middle for the whole session, around 3 hrs. I also just cleaned and re greased all the gears which might also play a roll. Ken

Yes indeed, that triangle in the middle is the cone nebula You can also see the Hubble's Variable Nebula at the top right Ken

My latest with the Star Adventurer. Never imaged this area before, interesting stuff up there. I'd wish I had a bigger scope to make some close ups. image and equipment info: Nikon d90(mod)TS72 APO + TS72flat settings: 432mm, f6, iso800, 360min guiding:ZWO asi120mcsTS 50mm guidescope Tracking: Skywatcher Star Adventurer software: guiding: phd2 Stacking: Deepskystacker 4.2.2 Processing: Adobe Photoshop CC, automated action set, GradientXterminator, Nik software, HLVG

Her are my previous attempts with the same data. They are all slightly different framed or rotated, it as just the way I liked it back then. Ken 1st edit 2nd edit 3th edit

When your post processing knowledge expand I find it interesting to go back to old images and see what results you can now pull off with that data. Decided to take on a 2018 image, the first time I imaged Andromeda with my new refractor back then. Processing went much faster and easier as before. This also might be the version which I prefer the most, I believe it's the fourth version so far. Every one had something to it but imo this has the most 'natural' look . Also in previous versions it was difficult to pull out the colors but with this edit all they 'appeared' during the stretching with very little need to use color boosting tools. I'll post the previous versions in the comment below if you want to see the 'progress'. The difference with this stack is that I used the drizzle function and custom rectangle in DSS, I thought it would be beneficial as my setup is slightly undersampled, any information on how and when to use drizzle is welcome. The most obvious error in the image here are the startrails, which is unfortunate, but as I said it was the first time on Andromeda with this scope and the fourth target with this scope. Didn't had everything figured out yet, max exposure time, balancing and such. Seeing these new results I'm waiting for Andromeda season again and take on that galaxy again, this time with guiding. Here are some details on image and equipment: - Nikon d610 stock TS72 APO + TS72flat settings: 432mm, f6, iso1600, 6.5hrs (60ec subs) - Tracking: Skywatcher Star Adventurer unguided software: Stacking: Deepskystacker 4.2.2 (drizzle2) Processing: Adobe Photoshop, several PS plugins and astro actions Ken

Definitely worth it yes. You can also wait until May when the comet is at its brightest. Ken

Thanks Dave! Yeah I was too excited about the comet so the processing went rather quickly Hope you get some good data. What equipment did you use? Ken

No problem. I've never used the Walimex though, so you'll have to do some test for yourself to determine it's best f stop. I imagine there will be some differences but from what I've read it's a really good astro lens and many shoot wide open with it, even better :) Ken

Just had a look at the raw and I stopped down to f4 and used iso 400 on the camera. At f1.8 the lens has some coma in the corners and a good amount of vignette. At f2.8 the coma is mostly removed but I'm not too happy with the amount of vignette. f4 did the trick for me. Ken