Johns22

I've finally managed to spare some more time on the Darkstar scope this evening. I think I now have everything here to complete the project, it's just a matter of time... Tonight I finally put my brave pants on and drilled the OTA for the new focuser fitment. I really wanted to follow the video above but I didn't have the right sized holesaw to use as the guide unfortunately. Therefore I had to revert back to mounting a piece of wood and finding centre with lots of measuring and double checking. Thankfully all went smoothly and the focuser fitted perfectly. I've since dismantled the OTA completely to give it a good clean down. I know I said I didn't want to paint it and I still don't want too but I have found a potential cool alternative. I have purchased some vinyl wrap from eBay and I intend to wrap the OTA to make it look a little different - and make it mine I suppose. This means I will be painting the mounting box and the swivel base just to smarten the whole thing up. I'm not sure how much further I'm going to get over the next week as I have my daughters birthday followed by a long family holiday but I would at least like to get it wrapped before I go - to see if I like it! 😁 Thanks again to those who follow this project!

I've made a little more progress today - and have collected the mirrors from Orion Optics on Friday. A 4 day turnaround was pretty impressive and the mirrors look excellent! I have mounted the Telrad finder properly, rather than it being stuck on with sellotape! I have also purchased some matt black spray paint and painted the spider and other secondary mirror fixings. The flocking material for inside the OTA has arrived from FLO but I want to drill out the hole for the new focuser before I fit that. Hopefully I can get the correct holesaw and some bathroom silicone sealant to attach the mirrors early this coming week so I can keep the project moving. Once the focuser is mounted, I will give it all a good clean, remove all the nuts and bolts into the OTA and get flocking! I'm trying to find something suitable to act as a band around the bottom of the OTA where it has previously split. The resin I have used has made a great job of repairing the split but it would be nice to have something additional. I have thought about a duct clamp which could also act as somewhere for magnetic weights to be attached for balance once it's all together.

I've managed to spare some time this evening trying to move forward with the project. My fix for the split in the OTA failed unfortunately. It seems the OTA is made from some sort of fibreboard rather than plastic. So I've cleaned up the surface around the split and used Gorilla glue to try and secure it and stop it spreading any further up the OTA. I've also measured up for flocking material - it does seem like a good time to do this. I've been cleaning up and measuring the teflon on the base ready to order that too. I had an email this morning from Orion Optics to say my mirrors are ready to collect. Very impressed with that quick turnaround - they will be collected in the morning. Collimator is on the way! I'm not sure now whether to stick with the original focuser or change to the Skywatcher. The reason for my doubt is that the Skywatcher focuser tube sits a long way into the OTA compared to the Dark Star original (see pictures). I'm also concerned that I won't achieve focus without altering where the mirror mounts. Any thoughts?

Thanks for this option. Just to be clear, you have a sheet of 4mm Teflon on the base and then the textured aluminum on the top surface? I understand what you're saying in regard to the bearing - I guess a low friction bearing could become frustrating when you're on target and a small breeze or sneeze causes unwanted rotation. I guess if the base wasn't perfectly level either, you would have to hold on to the OTA whilst viewing to stop rotation?

Thanks all! It sounds like flocking is the best choice then. I have seen people flocking scopes in the past but I didn't appreciate it's the preferred option. I didn't see any markings on the mirror before I took it to Orion - they guy there did also speak positively of it though when I mentioned it was out of a Dark star. On collimation, I have done this in the past. But not believing in my own skills, I took that scope to my local astronomy club where a helpful chap re-did it. He told me that I did have it collimated but not in the way he would have done it. I was then baffled in a subsequent discussion in the same room whereby some opinions were lasers were the best and others believed a simple collimation cap was always perfect. Do I buy a laser (which also needs collimating?) or a cap? I haven't ordered the teflon pads yet so will take a look at that Lazy Susan bearing this evening. Update: Just had a quick look and this appears to be a great piece of advice thank you @bosun21 - it even got a guy wondering if these could replace the yellow plastic rings on the scope (I really dislike the look of those)! Thanks again - I always appreciate advice or challenges on what I think is right!

About 18 months ago I was asked to collect an 'old' telescope locally which was taking up room in someone's garage. I did so one dark and miserable winter evening finding a blue dobsonian flavour scope which had been stored very badly, without any dust covers. The primary mirror looked in dreadful condition and the OTA was randomly wrapped in old plastic bags. Due to the weather and not knowing the person, I loaded it into the car and brought it home. It then stood in my workshop till now. Knowing very little about telescopes, I didn't fully understand what I had until very recently when I started searching the interweb for more information. I also (incorrectly!) assumed at the time that the telescope was of the 8 inch variety but having started to dig into it over the past couple of weeks, it's actually a Dark Star 10" dobsonian. I found threads on this group where people have done similar restoration projects to these scopes and I was sold on trying to save it. It'll be fine... 🤑 Earlier this week, I dug it out and removed the primary mirror which I soaked in warm soapy water for a time but it quickly become obvious it was not going to be saved. Unfortunately I didn't take any photo's of how the mirror was initially but you can see from the attached it is very bad even after some cleansing. Next I removed the secondary mirror which looked better but instantly separated from the holder in my hand. I'm surprised that hasn't got intimate with the primary before! 😳 After attacking the primary mirror silicon fixing with a wood saw, both mirrors have now been delivered to Orion Optics for recoating. Roll on 7-10 days when we'll then enjoy cloudy nights for several weeks! I was also puzzled as to why someone had bothered to wrap the bottom of the OTA in duck tape. Upon removal of said tape it became apparent that the OTA is split from the bottom up for a few inches. I have carefully removed the tape (and subsequently the old sticky residue left over) and it looks like it will repair. 🥴 So I'm going to do the right thing and replicate a hack I've seen on FaceSpace whereby using paper clips and a soldering iron, you can repair most plastic splits. I just can't find any paper clips right now - I'm sure the office will assist here! I've also purchased a Skywatcher single speed focuser from a friendly chap over on Astrobuy&sell which has turned up this weekend. I must admit I didn't really think about the size of it but it's huge! Much bigger than the existing Dark Star focuser but seeing similar stories on this forum, I'm going to make it fit! I just need a 58mm or 60mm holesaw and some timber to allow me to central the hole and drill out. Today I have taken the base apart as it tended to move the as one unit when swiveled, rather than the required 2 pieces. I see again from similar threads that some new teflon furniture pads should fix that issue. I'm already browsing the Jungleweb store for said replacements. I am considering respraying inside the OTA with the matt black paint mentioned elsewhere just to give it that brand new rebuilt look. I'm also impressed with some photos I've seen of others who have repainted the outside of the OTA but that looks like a big job - maybe too big for me. Plus, I'm feeling the 'patina' vibe with this telescope at the moment. Anything can change though right? I hope to have the OTA repaired and the Skywatcher focuser installed this week. I will post updates as I go. Any help/guidance/constructive criticism welcome!

Here is my first attempt at widefield astrophotography using a Canon 650D, Sigma 105mm Prime Lens and a Star Adventurer Mount. All taken at home under Bortle Class 4 skies, stacked in Deep Sky Stacker and processed in Pixinsight (my first experience!). Used a Optolong L-Pro clip in filter too. 92 x 1min 30sec Lights @ ISO800 f3.5 30 x Darks 30 x Flats 22 x Bias Constructive Criticism welcome.

Thanks all - long exposure noise reduction is disabled on the camera. This is what happens when you buy cheap product off Amazon I guess... Please can anyone recommend a good intervalometer - any links to purchase would also be appreciated.

Resolved - the intervalometer requires the interval between exposures to be set at least 1 sec longer than the exposure time... Is this normal for intervalometers? It means doubling the session time to capture the images.

I will check the mirror lock thank you. It was definately set to 60 secs - I watched it countdown, then the light changed on the intervalometer as it counted down on the interval before starting the next exposure. Meanwhile the camera was still exposing the initial image.

Last night I rigged up my Canon 650D with a recently purchased Amazon intervalometer - the camera was in Bulb mode. I initially set the intervalometer to 30 sec delay (to give me time to leave the area) followed by 150 x 1 minute subs with a 3 sec interval between exposures. An hour later I returned to the camera to notice the timer on the LCD display was up to 60 minutes for the exposure even though the intervalometer thought it was 50 images through it's sequence. After much cursing and selecting different delay / interval settings, it became clear that the camera does not stop exposing when the intervalometer reaches the exposure length. Instead the camera continues the initial exposure meaning you get one long exposure despite what the intervalometer is programmed to do. Has anyone else experienced this? This is my first experience of using a intervalometer, and don't particularly want to spend any more purchasing others if the problem lies elsewhere. I know I can use APT or another program to do this but I want a field based solution for future dark sky trips. Thanks in advance.

Hi Simon, Are you syncing Stellarium after you align each star? Once aligned in the eyepiece, you should go back to Stellarium and press CTRL-3 (by default) to align Stellarium to the actual star/object. I also put the laptop in a plastic box with clip on lid to avoid dew issues. Cheers John.

I chose the Canon 600D which has favorable reviews for astro modifying. I haven't modified it yet as with this being my first ever DSLR, I enjoy using it during the day too. I do use a Svbony CCD filter for light pollution - these are cheap at £40 - I would like to try the more expensive ones as a comparison. I picked up the 600D with approx 1000 on the shutter count, in the original box with all the accessories for £140 earlier this year. It's immaculate!

Thanks @Notty @Paul2019 and @geeklee - its great to see different takes on my data. Glad you enjoy working with it 👍

Thanks Tommohawk, I had seen the tip online to take flats in AV mode. I will try again on the next imaging session to just adjust the exposure to see if I can resolve this.

Thank you guys, I have little option but to persevere with it and I will be trying the tips outlined above. I have been letting the cables trail from the scope to the laptop (the guide cam 2m cable makes it difficult) but I have recently acquired a small powered USB hub which I aim to mount on the scope and then have some cable management. Appreciate all the comments, thanks.

Here is my first "successful" attempt at a galaxy! The Whirlpool Galaxy (Messier 51) taken on 25th March 2020 from my garden using a Skywatcher 200P, EQ5 Goto Mount, Canon 600D, ZWO ASI 120mm Guidecam on a Skywatcher 9 x 50mm Finderscope, captured using NINA, guided with PHD2, stacked in Deepskystacker and processed in Photoshop, using GradientXTerminator action and Astronomytools action set. I've found this really difficult to process and will probably spend time reprocessing in the future to find my preference but we have to start somewhere! 289 x 40 sec Lights @ ISO 800 40 x Bias frames @ ISO 800 30 x Dark frames @ ISO 800 20 x Flat frames Stacked file also attached for anyone who would like to show me the error of my ways! Autosave.tif

Thanks, I will try the east heavy balance tonight. I have entered 190mm for the focal length of the guidescope (following advice on others using the standard 50mm finder on here with the camera). If I get chance before setting up tonight, I'll post the guide log file. The imaging camera is a Canon 600D unmodified. Cheers John.

I've done this, this week with Adobe Bridge - free to download and you can select any number of images before rotating. I also use it to check image quality before stacking. https://www.adobe.com/uk/products/bridge.html

I've recently purchased a guidecam (ASI 120mm) from the helpful guys at FLO in the hope of increasing my exposure time. My first night of trying to guide was a nightmare last Sunday night with calibration taking ages and then the correction graph looked like a portrait of the Alps... Monday night I discovered that you really need to nail your polar alignment for guiding to be effective, so I invested in Sharpcap Pro. Wednesday night I got all of this working, SharpCap polar align said it was Excellent, PHD2 caliberated quicker (had an advisory on DEC backlash) and showed far less adjustments when guiding, I set focus with a bahtinov mask and then run my first few 60 sec exposures to find significant star trails. I ended up doing 40 sec exposures which were the absolute maximum before trailing became an issue. Rather disappointed having shelled out a few hundred quid! I'm running a Skywatcher 200P on an EQ5 Goto Mount, guided with a ZWO ASI 120mm fitted to the standard Skywatcher 50mm finderscope. Am I pushing the mount too far with a DSLR and guidecam fitted? Could the guidescope need realigning with the OTA? Have I missed something really fundamental? I plan to image again tonight and am keen to understand the errors of my ways! Any help very much appreciated.

Hi Michael, The camera was directly connected to the scope when the flats were taken so not sure why the photo's say a 50mm lens was attached. Could this be a setting in the camera? I haven't changed anything in the settings in relation to Auto rotate - should that be set? Cheers John.

File info shows 1/2000 sec. 50mm @ ISO800 with 2 layers of t-shirt, then 1/2500 sec. 50mm @ ISO800 with 1 layer of t-shirt. This suggests the AV mode has detected the change in light? Files attached as above, in case there's any clues... IMG_1499.CR2 IMG_1539.CR2

This morning I attempted my first flat calibration frames on my Skywatcher 200P, using a white tshirt and the morning sky at 7.15am. Setting my Canon 600D SLR to AV mode, I took 20 photos but all were completely black. I repeated the process with just one layer of the tshirt over the scope but still they were completely black. At this point, the sunlight was across the tshirt but still the images were completely black. I did check all lens covers were removed! Please can anyone advise what am I doing wrong?

Thank guy's, that's very helpful. I have yet to take Flat's but am planning on doing so during the next session. Do you think that is the main issue with the gradient? I do suffer light pollution before 12am which is why I purchased the Svbony CCD filter. I wonder if it is this filter also causing the issue as I'm aware there are more expensive alternatives available. I really like both images above for different reasons - thanks so much for taking the time to show me how you would process the image. 😀

Here is the original stacked tiff file for the above image. Feel free to process and share tips/tricks with me! Autosave.tif