Jonesdee

Interesting, that's exactly what my Rice Crispies told me!

Hi Vlad As you say, a fun exercise. some more info - it was shot with an FSQ85 plus Field Corrector (455mm) using ASI2600: Dave

Not sure if surveillance satellites can alter course, but if that were the cause, it must be pretty manoeuvrable! I think I agree with Enigma_RL - must be aliens

Yes, good thought @Tiny Clanger. It was a 3 minute exposure and a rocket could have passed over at relatively low level and registered on the sensor. Much more interesting than the Space-X stuff !

I wondered that too James, but these usually show multiple trails from the various lights on board. Possibly something flying very high?

While discarding poor subs last night, I came across this - plenty of trails from Mr Musk's toys, but what is the wandering object on the right? Anyone seen anything like this before? Dave

All Thanks for your input - I will start again from scratch and reprocess the data. Will post the results . . . Dave

Hi Stuart, thanks for your reply. Interestingly I cannot see the issue in either individual subs or the master flat. Good to know that you do not use the flattener as this points to an issue with the main optics of the scope. I will check with a torch as you suggested, however looking through the OTA at the sky seems clear.

In October I broke the piggy bank and bought an FSQ-85ED, which was supplied with the 1.01x Flattener. Given our rubbish weather, I have only had a couple of opportunities to use it, the first being with my ASI1600 mono. I had the flattener fitted for that session and was pleased with the results. In December I purchased an ASI2600 OSC and fitted that to the Tak without the flattener, first to save the aggravation of setting accurate back focus and secondly because it should not be needed for that sensor size (the flattener is supposedly only required to correct astigmatism with full frame sensors). I imaged M52 and IC1805 in the first session and noticed that the centre of the stacked image appeared to be very bright., despite being calibrated with flats, dark flats and dark frames. Using DBE in Pixinsight I was able to reduce the flare, but it returned quite significantly when noise reduction was applied to the image . Next clear night I imaged close to M81/82 with dark sky in the centre of the frame. Sure enough, there was a bright circle in the centre. Suspecting the ASI2600 to be faulty, last night I repeated the test with my ASI294, expecting it to be fine. Unfortunately the same bright patch was present, pointing the blame at the scope instead of the camera. Here is a (slightly cropped) screen grab of the ASI294 image. Subs were calibrated with darks, flats and dark flats, stacked and for quickness, gradients removed with ABE in Pixinsight. No other processing performed . The issue is very clear even in a low-res snip: Has anyone experienced anything similar to this? I wonder if use of the 1.01x flattener is mandatory with the latest FSQ85s, i.e. have the main optics been changed to better work with the flattener which is now supplied free of charge with the scope? Next test will obviously be to try one of the OSCs on the scope with the flattener fitted. Cheers Dave

I recently needed to make a couple of custom length power cables and purchased some of this: https://www.ebay.co.uk/itm/163699838807 It is extremely flexible and appears to be of the same quality as that used by commercial suppliers. Maximum current is 4 Amps, however it runs the coolers on my ZWO cameras without issue. I am not affiliated in any way to the seller, just wanted to share details of what I believe to be a very useful product for the DIYers amongst us. BTW I asked the seller if he had any 4 core in the equivalent material (for focus controllers) but that is not something he stocks. Cheers Dave

Canon 100D if they are still available. Very light weight, 18Mpx and do everything that's needed for astro via Backyard EOS. These days I mainly use cooled ZWO cameras, but keep the 100Ds for use with my Star Adventurer (I have 2 - one is fully modded, the other has just the IR filter removed.) Dave

As someone whose main interest is imaging, I share these concerns expressed in this and the earlier thread. My thoughts on the problem are as follows: Prior to the launch of the first SpaceX satellites, I would typically see satellite/aircraft trails in fewer than 5% of my subs and as Olly says above, these can be processed out. Where I live in Wiltshire, aircraft are a bigger problem than satellites, so probably only 2% of my subs have been impacted by satellites. I therefore hope that even a 10-fold increase in satellite density will still be manageable using my current processing methods. Again, echoing Olly's comments on CMOS sensors, in my sky-limited suburban location exposures are typically 1 to 2 minutes using an ASI294 OSC and 2 - 5 minutes with an ASI1600 Mono and RGB or NB Filters. To be honest, the UK weather is a far, far, bigger problem for me. It is almost 2 months since I had a clear enough night to get the kit out and even on a 'good' night, more subs are spoiled by passing cloud or rising mist than man-made objects moving through the fov. That said, it is frightening that, having polluted our planet close to the point of extinction, we are now starting to do the same with space . . . Dave

You are absolutely correct - the Yongnuo is a 100mm f2 lens. My mistake, I was confusing it with a Canon 200mm that I have borrowed from a colleague (and sadly has to be returned). Value for money, the Yongnuo is great, however the autofocus is not brilliant if you want to use it as a general purpose lens. I focus it with the controls in Backyard EOS, or just do it manually. I will edit my original post!

I guide mine with a 60mm Altair Astro guide scope, GPCAM2 camera and PHD2 software. This setup also allows me to get fairly quick and accurate Polar Alignment using the PHD2 Drift Align Tool. Ten minute+ exposures are then possible (using a solid tripod of course). I control the camera (modded Canon 100D) via Backyard EOS, which can also enable dithering via PHD2. I bought my Star Adventurer to avoid the long setup time required by my full size scopes and am delighted with it, although since completing my observatory it doesn't get so much use. I mainly use Contax 50mm f1.8 and Yongnuo 200mm f2 lenses. The Contax is excellent quality glass with full manual control and can be picked up cheaply these days. Dave Cygnus.tif

Cheers Kev, I hope we get some decent weather soon to give it a proper try! Just to have the mount set up and ready to go is a massive benefit. Being a very compact obs, I can mount the scope through the shutter opening, so it is not necessary to climb inside too often. Next step will probably be a motor to rotate the dome, but I don't see that as a critical item yet. With the 80mm refractor, it appears to take around an hour to track from one side of the slit to the other Dave

Cheers Steve Yup, you just cannot have too many clamps! Being a keen woodworker for many years, I have aquired a good selection of tools to make a task like this relatively easy to accomplish. Also, being almost 70 now and recently retired, I have the time to spend on projects like this (certainly beats working!) Dave

Many thanks Steve, I'm itching to get to use it properly - at least today's weather has proved that it is waterproof Dave

Hi All Having lurked on this forum for about a year and made a couple of good purchases from the classifieds section, I thought I would share details of my recent project to construct a mini observatory for astrophotography work. Having personally learned a great deal from SGL, I hope this may assist anyone considering a similar project. After a lapse of more than 10 years, I got back into astronomy last summer with the purchase of a 200mm Dob, but soon graduated to a second-hand EQ5/200P with the intention of motorising the mount for photographic work. I followed Tom Carpenter’s excellent instructions for fitting stepper motors and built one of his AstroEQ controllers which works very well indeed. I now use this with either an 80mm refractor or 6” R-C, given the excessive weight of the 200P for imaging. Thanks to our weather, it soon became obvious that there are many advantages to having the mount permanently set up and ready to use at very short notice, hence the decision to build the observatory. Part of the motivation was the challenge of constructing a dome, plus an overall design which was small and would not look too obtrusive in the garden. It was never intended to be used for visual observation, so an overall dome diameter of 1.2 metres gave sufficient space for full movement of both OTAs with SLRs/filter wheel fitted. A selection of photos of the build can be found here: https://photos.app.goo.gl/g9DnEucfvhZyHZWr2 The dome is constructed from 18mm ply framing with 3.6mm ply cladding, which was laminated inside and out with glass cloth/epoxy resin. It rotates on 6 rubber-wheeled castors with another 4 mounted horizontally to keep it central. The main shutter runs on 4 transfer rollers with an additional 4 mounted vertically to ensure it does not jam when opening/closing. The base structure consists of 8 OSB panels with strengthening battens. These fit between eight 45mm x 70mm uprights which support the weight of the top panel and dome. OSB is not ideal for outdoor use, but the entire structure has been painted with exterior undercoat and three topcoats, so it hopefully will remain weatherproof for a number of years. The entrance hatch is fitted with surface mounted S/S hinges and an espagnolette lock. The main shutter overlaps the lower hinged flap by 50mm to help with weather proofing and two sliding bolts hold it shut when not in use. The pier is a 900mm length of 168mm galvanised steel pipe, filled with concrete. The ground at our location is difficult to dig due to layers of limestone rock below approx. 600mm deep. For stability, I drove a 2m length of 35 x 35mm steel angle down through the rock prior to pouring around .5 cubic metres of concrete into an appropriately tapered hole. Short brackets mounted on the angle hold 4 lengths of 8mm rebar which are spiralled into the hole for added strength and support of the steel tube. The adaptor plates started life as two 200m x 200m x 12.5mm square plates, separated with 4 lengths of 16mm threaded bar. In addition to levelling, these enable the height of the mount to be adjusted, to accommodate full movement of the scopes inside the small dome. Once the mount and scope were fitted, it was clear that the corners of the plates could collide with the camera or filter wheel, so I resorted to cutting the plates into discs with my woodworking bandsaw (actually a surprisingly easy task) and repositioning the 4 x 16mm rods. I have only managed to use it twice since completing the build, primarily to drift align the mount, hopefully I will follow this post up with some images in the near future. Any questions, please give me a shout Cheers Dave