NigeB

Brilliant result Steve - congratulations!

Hi Steve, That's interesting. I'm toying with the chain approach and have had a very helpful exchange with @hughgilhespie regarding the design of his system, in parallel with the discussion with you here. I'm reluctant to give up on the belt yet - you've clearly managed to make it work, and actually seeing some of Hugh's solutions to the chain guide, has given me an idea for improving my implementation of the belt drive. I got the dome rotation working at the weekend (relief!), but in doing so I realised that the pressure needed between the pulley and belt to get skip-free performance was somewhat more than I'd expected. I can't possibly get that on the shutter in the current version. But I can now see how to mount a metal support frame inside the top of the dome to achieve that. Combined with a higher torque motor, I think this might work - and if not, the motor will be useful for the chain. Re: sliding mechanism. It's quite a nice design - the shutter has a set of plastic (maybe PTFE) cylindrical blocks bolted to the inner surface of the sides. These engage in a wide groove which is moulded into the outside of the raised lip which runs on either side of the slit from front to back. The groove is closed at each end so once you bolt everything together, the shutter slides smoothly back and forwards but can't drop out. For now I'm going to focus on getting the rotation finished and stick to manual shutter, but as soon as that's done, I'll upgrade the shutter motor/mount and see what happens. Thanks again ! Nigel

Hi Steve, Many thanks! Interesting, slippage is what I'm also seeing (but only the first few cm, which I understand in terms of the force exerted by the shutter at that part of the travel, and I think I may be able to fix it with some better spring tensioning design for the motor mount). I can see how the wheels you've implemented would help this. The other problem in my case is the lack of torque from the wiper motor, and that's more fundamental. Those planetary gear motors are much better from that perspective, but tricker to mount - however, I may need to embrace that challenge. In parallel I'm also weighing up the chain approach which @hughgilhespie has implemented. Your system seems to work beautifully. But the 2.7m shutter is pretty heavy, and I'm slightly concerned that for this reason, the timing belt might be "on the edge" for shutter operation in my setup. At least the same motor can be used for both approaches, so it's not a big financial hit to try one then the other - but I want to avoid cutting the dome and then finding I have to adopt the alternative approach. Some temporary fixings may be in order. I've also got MagicWire as part of the system (I had some exchanges with you via the SGL messages channel a while back) - the boards are made up and seem to be functioning. It's just those awkward little mechanical gremlins that I need to combat! I put a telescope in the dome for the first time last night. Even though the automation is not ready yet, I can't stand seeing the clear evenings we've had lately and not be able to at least take a look at Mars and the moon... Thanks for your ongoing postings - they are really the primary guide I've been using to implement the automation of my system. Nigel

Hi @sloz1664 Steve, That looks absolutely fantastic! As you know, I've been following your work and implementing your design in my 2.7m Pulsar. I've got the timing belts fitted, and am about to test the rotation. However, I've already tested the shutter drive and found that my 12V wiper motor isn't up to that task. I can open and close the shutter, but it's a heavy shutter and the load on the motor changes significantly across the range of travel from fully open to fully closed. The torque available is not enough to keep the movement under control. I see from your images that you're using what looks like a planetary gear motor. I've been looking at these ones: https://gimsonrobotics.co.uk/categories/dc-electric-motors/products/gr-ep-52-high-torque-planetary-gearmotor-12v-and-24v-versions and they have much higher torque and lower output speed than the wiper motor - plus the smaller body diameter means I can use a smaller timing pulley without the motor body catching on the shutter, which will also help. So this seems like a better choice - and as far as I know is similar to the ones used in the off-the-shelf Pulsar solution. Does this look sensible to you - and could you tell me which motor you've used? And one other question - can you explain how, in your bracket, you've managed to support the motor at the end opposite the pulley? There's obviously enough play in that to allow the spring to keep the other end in contact with the belt. Very nice. Thanks! Nigel

Mr P. has brought me a toy from Altair... I decided I wanted to consolidate all my small cabling, power and connectivity problems into one big one And it came with Haribo. Based on the veneer of stickiness my kids leave after Haribo, these may be quite effective at fixing the box to the telescope... Seriously, it's well made - the outward appearance seems to have changed slightly compared to the first v2 units. Looking forward to fixing it up - alas I pulled down my wooden observatory a month ago and haven't yet finished setting up the dome, so it may be a few more weeks before I get to try the Power Box out. But it's going to significantly reduce the amount of "stuff" around the telescope and make full robotic use with power control a bit easier to achieve. Nigel

Thanks Kinch, Laurin Dave - great; I'll ask him to post them up. Nigel

Hmm: good point thanks! Fixed it...

Hello All, I've just become the owner of a used Pulsar 2.7 metre observatory. It's come with no keys (fortunately the door is unlocked!) The previous owner has sent me a photo of some keys, but he's not sure if they are for the observatory (he bought the dome second hand last year but had planning permission refused and never got to set it up and use it). I think this is a "Mk II" design. I've attached a rather poor photo of the door handle, and the keys. For those of you who own Pulsars with this kind of handle - do these look like the right keys? Thanks Nigel

That's spectacular! Nicely done indeed.

I watched the talk live last week - it was excellent - looking forward to the next. Having access to these recordings is a fantastic resource. This is a real service to the community - many thanks to the speakers and SGL team for putting in the effort to make this happen. As far as I can see this is a pretty unique initiative for the online astronomy community and you're setting a high bar for others.

Hello All, This is a bit of an odd one. I've bought a second hand observatory dome - it's a 2.9m AstroDomes one like this: http://astrodomes.com/2-9m-fibreglass-astrodome/ It's in Sussex (Lower Dicker - BN27 postcode). Once the Covid restrictions are relaxed enough to allow it, I need to go down and collect. It breaks down into two main sections and a few other bits (see photo). The two main sections are quite large, and likely to weigh around 160 kg each. So it's more than a 2-person lift. Aside from me and the seller, I'm probably going to need 2, possibly 3, other people to help me get the sections on the back of a dropside van. Obviously I can't do any of this until Covid rules permit it. But I'd like to ask if there are any SGL members in that area who might be willing to lend a hand for an hour for some lifting when that happens? I'd be happy to cover their travel costs and a bit more for their trouble. If I get any responses then I know it's possible - if not, then I'll have to look at alternative shipping. Please don't respond if you have a bad back! Thanks Nigel

Looks like a good one - really stable PHD2 plot. 600 sec sub on NGC3718 just in...

Excellent - nice colour detection as well.

Hi All, After a hiatus due to other commitments, I've managed to get back in the observatory. Late last month I upgraded the computer, which was starting to creak somewhat, and I spent an evening swapping out machines and sorting out software configurations. I'd forgotten how many things have to be configured and all the bits that can cause a session to grind to a halt... At the end of the evening I used M51 as a test to make sure Voyager control was working properly. I didn't take much notice of camera orientation - it was simply meant to be a test run, but we then had a sequence of good nights and I just kept going, so the data set was pretty good at the end. I've had some great advice from SGL members about processing technique in the past - see e.g. my Whale post here and all the brilliant responses. For anyone trying to understand Pixinsight processes, there's a lot of useful information in the thread and it helped me enormously. For this M51 data set I tried to delve a little deeper into the process and understand a few more of the processing options and settings in PixInsight, including combining Ha with LRGB, and some more mask-based work. The result is below. I know I have a tracking issue that needs to be adjusted out, and I think there's a softness here which isn't so evident in the raw files, so I have probably over-cooked some of the processing and mask protection. I'm going to have another go, but I think after 2 days of being absorbed in tutorials and Pixinsight sessions, I'm probably pushing my luck with my family and need to go and plumb in the dishwasher, which will no doubt take a week to sort. So here's the result of the last few evenings of mis-spent time... Comments and suggestions welcome! If anyone wants to try processing the data, I've put the calibrated and stacked files on Dropbox here: https://www.dropbox.com/s/uzhrwsuyaupsfsn/M51_Stacked_And_Aligned.zip?dl=0 Nigel