Hughsie

Nice captures by you and the young ‘un. Cloudy and blowy here, not much chance of seeing anything until much later.

Had an interesting morning yesterday. Spent Thursday night imaging, then Friday morning I collected my calibration frames for my new target, watched the rocket launch to the ISS then saw it was still clear outside so grabbed the scope to see what the Sun was up to. Here are a selection of images taken on 23 April 2021 showing the active regions, filaments and prominence on the Sun that morning. Equipment 60mm Lunt LS60THa/B1200CPT scope. SkyWatcher Solar Quest mount. ZWO ASI174mm camera. TeleVue Powermate 2.5x and 5x for close up images. All images processed within PixInsight. Thanks for checking in.

Thank you. Not too far from the border with Suffolk, in fact I can see it from here!

Currently I am touring Canes Venatici and the galaxies it has to offer but I am trying to avoid the ‘usual’ candidates. First up is NGC4490 & NGC4485 aka the Cocoon Galaxy. This is approximately 25 million light years away and shows the two galaxies interacting as they slowly merge. Next is another pair of interacting galaxies, this time NGC5395 & NGC5394 aka the Heron Galaxy. These two are 160 million light years away. Both were first observed by William Herschel about a year apart. In fact the Heron Galaxy was discovered on 16 May 1787 so probably a clear night for Ye Olde Astrophotographers and their Box Brownies.

Hi Michael. I was on a dev version of PHD2 and reloaded a previous version (before the multi star). Previously I was guiding with a ZWO ASI290mm mini which was producing a pixel resolution of 0.49. Fortunately I have a Starlight Express Lodestar X2. With this plumbed into the imaging rig and with a pixel size of 8.3 the resolution stepped up to 1’. Now I have no guiding issues.

I have recently switched to using an OAG with an RC8 and prior to this had no issues guiding with SGPro and PHD2 with a guide camera and guide scope. The issue I have is this; I commence my imaging sequence, the scope slews to target, plate solves and then starts PHD2. PHD2 opens up and connects to my guide camera and SGPro awaits guiding to commence. Meanwhile PHD2 cycles through 3.5 s images, auto selects a star and commences guiding. RA OSC is reported but RA and DEC errors remain at zero. The RA and DEC trend lines continue as you would expect and PHD2 is making adjustments. Back to SGPro, it is still waiting for auto guiding to start and hence the image run doesn’t commence. I have reasonable focus on my guide camera and there is a dark library in place for my guide camera. SNR on the guide star is good. Has anyone experienced this before and if so, what adjustments did you make to correct it. Thanks in advance. John

I have presented a few images here over the last two years and received ‘likes’ which is always nice. This last 24 hours Vlaiv has presented a critique of my image far and above anything I have received so far which has challenged me to consider what I feel is the ‘norm’. Having acknowledged his assessment, I undertook my own review of on the points he raised and have learned that this is not the first time he has called out the demerits of DrizzleIntegration. From my own personal perspective I really welcomed this challenge. Spending hours in the dark freezing cold I always aspire to produce the best that my scope/camera can see. To be better requires good constructive feedback and Vlaiv has provided that over the course of this weekend. Thank you Vlaiv.

Hi Vlaiv, my observations are as follows; Drizzle integration was dropped from the workflow. Rather than undertake a Histogram stretch to move from linear to non-linear data, I used MaskedStretch with the background set at 0.10. This really helped try and keep control of the star in the bottom left hand corner. Noise reduction. Having combined RGB then L to RGB, the noise in the image was so much lower. I cloned the LRGB and ran TGVDenoise on it and compared with LRGB with no noise reduction and it was tough to call whether noise reduction was needed. Visually, the ‘north’ side of M82 in the new image is showing slightly more detail than the original. It's tough to see in png format but the original xisf side by side this new version shows more detail. I agree, the ‘glow’ from the galaxy is more apparent and smoother. The stand out for me was the low level of noise by not incorporating DrizzleIntegration into the workflow. This made the image so much easier to work with. Secondary to this the larger stars appear more tighter. John

I have gone back and re-processed the image following Vlaiv’s comments. I can’t re-capture in Bin 2 but I have removed Drizzle Integration from the workflow. Thanks again Vlaiv, really good feedback.

Thank you Vlaiv, that is a really helpful explanation.

Thank you Vlav. I did drizzle with the ASI1600. What are the advantages of x2 binning over drizzle?

Thanks Craig. I went with the v2 ZWO OAG and it came with the Helical Focuser too. I set it up during the day, focused my main image camera then adjusted the guide camera until it came into focus too.

This was the second outing with the RC8 this time taking a look at Messier 82. In 2020 I captured this galaxy along with Messier 81 with my 4” refractor and when I purchased the RC8 I really could only think about pointing it towards M82 first. That starburst region is so dramatic. This image was captured during one night and is presented in LRGB. Exposure time was 120s across each filter with a total integration time of 4.3 hours. More data was captured earlier in the week but I had to bin it. Whilst the scope was guiding well I came across flexure for the first time and over the course of a night I watched my images drift consistently in one direction. The next day "Operation Tighten Everything" kicked in and that night I hoped I had solved the issue but sadly I hadn’t. "Operation Acquire an OAG” was a challenge and solved with an eBay purchase. Then “Operation How The Hell Do I Use This Thing” started. Nothing new there! The rest as they say is history and “Stella” as my RC8 is now known continues to throw out challenges. But when you can get this close to M82, I don’t really care.

Unless you have a desire to splash out on a high spec machine, I would consider a reconditioned desktop. I recently purchased a Dell Optiplex 790 short form factor (SFF - smaller and more compact) and they are very easy to upgrade. I bought one last year for c£300 via Amazon with an Intel i3 and 8GB of RAM + 500GB spinning hard disk. Now it’s got an i7 installed (£90 off eBay) 16GB Ram and a 500GB SSD (from Crucial UK) plus a 2TB Hybrid SSD hard disk for storage (£50 off eBay). You can get cheaper 790’s on eBay, but sometimes there is no warranty and if something was wrong with the item I would prefer to argue with Amazon to get my £300 back. Just want to add that I am not a skilled IT individual, however, there are some very clear YouTube videos out there that show you what you need and how to install it.

I use PixInsight and it is a steep learning curve when you start out with it but I feel it is worth the effort. I agree with the earlier post, make use of the trial and see how your pc copes. Also, you can practice using the data released here from the IKI observatory as well so no need to worry about how many imaging sessions you can get in over those 45 days. I imagine PixInsight will just run slower, however, with the learning curve a slow pc give you that ‘processing time’ to read Warren Keller’s second edition, Inside PixInsight. It’s available from all good bookshops and some rubbish ones too (always wanted to say that!)

I have come to the conclusion that they are so consistently inaccurate that it pays to do the complete opposite e.g. Forecast for Fire & Brimstone.....Set up your gear!

Aye to leaving the Bahtinov mask on. Also a first for me was sitting inside watching the guiding on PHD2 suddenly become erratic and then finding the cat was rubbing around the tripod legs! 🐈

With solar imaging it is important to understand that the ‘surface’ is dynamic and constantly changing. To render an image of the Sun or, say the Moon, you would typically capture a short video and stack the frames to create the image. With the Moon I would typically take a 10,000 frame video but with the Sun so much can change over 10,000 frames that it’s pointless taking it so a much shorter video is needed, say 500 or 1,000 frames. You can further improve the image by having a fast capture rate. If you compare the 178 with the 174 you will see the frames per second for the 174 is so much better. As a result the 174 will capture 1,000 frames much quicker than a 178 over which time the surface of the Sun will have not changed that much. There are however restrictions, for instance, can your computer download speed keep up with a high frame rate? USB2.0 will limit download speed compared to USB3.0 and are the images being written to an SSD or mechanical hard disk? I use a 174mm connected to a Intel i3 laptop, USB 3.0 connection writing to a Crucial 500GB SSD. Using my Lunt 60mm and 174mm at full resolution (Mono8) with SharpCap at 2.5ms exposures and zero gain I achieve a frame rate of c150FPS on a full solar disc image. I should add that I use SharpCap Pro (£10 per year fee) and with that you can also adjust up to 50% of you installed RAM towards buffering and so reducing the number of dropped frames. So, this is my take on the 174mm. Others here will have an opinion on the 178 or indeed what I have said here. Overall I am happy with the 174mm and if you want to see what a 174mm can do have a look at some of the Solar images I have posted on this site. Good luck. John

Hi Francis, I did read your exploits with your own RC to give myself some inspiration and guidance so thank you for your posts.

I had no prior experience with collimating at all never mind with an RC and read so many articles here and on other websites plus YouTube channels. For what it is worth, don’t take your scope apart. First, check the secondary withe a Cheshire to make sure the donut is centred and see if visually your primary mirror looks concentric. Then put it under the stars and see what they look like before making any adjustments to the primary. If the primary needs adjusting read this article http://www.deepskyinstruments.com/truerc/docs/DSI_Collimation_Procedure_Ver_1.0.pdf When you are familiar with the contents and assuming your primary needs tweaking then put the scope under the stars again and adjust the primary using the method above. If you have a long garden you could use an artificial star and make the adjustments during the day. Whatever you have to do, make small adjustments only. I did none of this and threw myself straight into it and got the pain I deserved. In the end I had to screw down the primary tight then loosen the screws three turns each to ‘reset’ it then collimate it. This could have thrown out the focal length of the scope so after getting what I thought was a collimated mirror I took a quick image, uploaded it to Astrometry.net and held my breath. I was lucky and the focal length was just a few mm out.

To say this has been a major source of frustration would be an understatement. After months taking myself off into the garage in all temperatures and fiddling with mirrors, screws and whatnots, Friday presented an opportunity to put the RC8 through its paces. All the usual niggles of finding the focus point, then a bad USB cable stopped images downloading and I managed to get started reviewing collimation under the stars. Having got to where I was with collimation I needed cheering up so pointed it at M97 and snapped away for 3 hours to see what I could capture and produce. So here it is; I wasn't fussed about framing, I just wanted to see something, anything just to assess whether this was a project heading in the right direction. It's getting there and I feel much better than I did with this scope a few months ago. Onwards and upwards!

Weather continues to be poor but there was a small window this morning to capture a single image of the Sun low in the South East. Clouds rolled in before I could even think about grabbing a barlow for a close up. AR 12808 located W on the disc and a flare region SE of centre. Few small prominences on the SW limb. Thanks for checking in. John

Lovely captures Neil, nothing wrong with those shots.

I read that Elon Musk once suggested that one way to warm up Mars for terraforming was to set off nuclear bombs at the poles. Not sure if he was serious or not but as he would like to go there I will give him the benefit of the doubt.

Open clusters are good targets with a Moon present or if you know clouds are only a few hours out. They are bright enough to get great captures like you have in a short space of time.