Sorry folks, I have been a bit lazy of late and not updated this blog to show the finished observatory!
It’s all done, well except for a couple of bits of edging that can wait till next spring…… Getting the Skyshed Pod assembled was not too hard with the help of my mate. I would say it took maybe an hour and a half tops – very easy to put together, even mounting the dome was quite straightforward, although a lot of the hard tricky time consuming work had been done by the previous owner – all we basically had to do was bolt it together and sit the dome on top!
So, am I happy with it? Yes, overall I am, its easy to use, feels very solid (even though its made from plastic!) and has a surprisingly good amount of space inside. I have one pod bay with the laptop in it, I sit on a small camp stool in the main observatory to access it. The observatory takes my 8″ F4 Newt, although I don’t think it would take anything longer, due to me offsetting the pier in order to gain better access to the meridian. Speaking of the meridian, even after offsetting I still cant get to it! Not a huge problem, a small sacrifice to make to get the convenience and security of the observatory and I could purchase I pod zenith table that would allow me to slide the done back but I’m not sure I need it….
The pod was quite a bit away so myself and a mate hired a Luton van with tail lift and away we went! Left Edinburgh around 10am, got home about half 6 and unloaded to the back garden.
This weekend I had planned to get decking, a pier and the observatory assembled, however due to the usual Scottish weather it rained from Friday afternoon until Saturday afternoon, so the whole garden was like a swamp and as a result we decided to leave the decking until Sunday. So I am now a little behind, but am determined not to rush things as I usually do…. The decking is complete, my brother in law who is a joiner (and laid the decking) is making a box out of wood that will slide through a hole cut in the decking and should be pointing north, time will tell!
Well, it’s been ages since I updated this blog! I moved house in April and have obviously been a bit busy then it was summer etc it’s only now that its getting dark at a reasonable time in Scotland that the kit can come back out….
So, I no longer have an observatory, I am setting everything up in the back garden each time, I was actually surprised how easy it was to polar align with the excellent EQMod software Polar Alignment utility, it seems ages since I have done this! Anyway, I do have tentative plans to purchase a SkyShed Pod dome next year but that does depend on money, and since it is shipped from Canada might take a while to get here and then I have to work out how to get it from Norfolk to here……. Fingers crossed anyway, it looks good, is quite a bit cheaper than a fibreglass dome and should be ideal for me 🙂
Last night was clear, although the moon was around but I wanted to test my William Optics ZS70 with the new field flattener (I used a 0.8 Reducer but was not too happy with the blue halos round stars so after a chat with Altair Astro I sent it back and got the 1.0x flattener). I had a couple of problems, the first was that my target was the double cluster, lots of stars to see halo’s round, but for some reason even though the plate solve worked it was not what appeared on screen 😦 so my 10×5 min subs are of a pretty empty star field! Secondly, I think I still have spacing issues, my setup isQHY8, IR Filter, Extension tube, OAG, Flatten. Today I took it apart and reduced the spacing by a tiny amount, maybe under a mm but we will see (hopefully) tonight if it improves it any.
Look at the corners, in 100% resolution and you will see what I mean.
Well, I have been a busy astro imager…… This past couple of months I have been hard at work trying to automate the observatory 🙂
First up was to get the roof done, I bought a garage door opener from Ebay and somehow managed to shoe horn it into the observatory, TBH it was a lot easier than I thought it would be…. The opener has a metal track that comes in three sections, 2 sections was perfect to have the motor stuck on a shelf in the warm room and the track the full length of the cold room. I also did a bit of work on the roof – previously the roof had some castors that rolled along a routed bit of wood, this was far from ideal, the wood was not perfectly square, neither were the castors, basically it worked but was very hard to operate. I got hold of some metal ‘V’ track used for electronic gates, such as you would have at the end of a driveway and the the rollers to go with the track. This means the rollers sit on the groove on the track. This was the hardest part, getting the track fitted but eventually with the help of one of my neighbors we managed to do it without lifting off the whole roof (which is very heavy, its a 3 man job to get it off and on). Anyway, now I can move the roof open and shut with a single finger 🙂
So… Back to the opener, I fitted that, cut the belt that was too long as I was only using 2 lengths of track and away it went! press the button on the remote and roof opens!
This was good but not good enough, the plan was for me to be able to open, start imaging and close at the end, the remote just allowed me to open and shut the roof… I invested in an Arduino, which is basically a small computer, that has a number of inputs and outputs, all controllable by software. Now it just so happens that I moved job a couple of years ago and have been learning the art of C# programming so I set myself the task of writing a small application that would ‘talk’ to the Arduino and allow me to open/shut the roof, power on/off the mains to the scope and camera and park/unpark the mount. I also wanted to know when the roof was open and when it was shut so that (hopefully) I could set an imaging run off, go to bed with an alarm set, waken up and close everything down, secure in the knowledge that the roof was closed. To do this, I ordered some of those magnetic contacts you have on windows and placed them at both ends of the track, the idea being that the trolley that pulls the roof along would have a magnet stuck to it which would trigger the contacts and let the software know the roof was open/shut. This however did not work – the repeat-ability of the trolley is not 100% and often the roof would be open but the contact not triggered, another solution was required….. This time, I went for a couple of microswitches, and this works a lot better!!
Back to the software….. So I have a little bit of code in the Arduino, this sets certain outputs high or low, I have one output connected via a relay to the roof opener contact (Now I dont need to use the remote, just the button on my c# app), another via a second relay to the mains power and 2 inputs that are connected to the microswitch at each end of the track. The inputs are read and if it detects the roof is open, a word is sent over the USB bus to the C# app, the same for the roof closed, mains on etc etc The c# app, runs on my imaging laptop, I can manually open/shut the roof, power the mains, connect to the scope etc, or I have a couple of buttons that do it all – click a button, the roof opens, the scope unparks, click another, the scope parks, then the roof closes – nearly everything needed for remote imaging, I already have full goto with plate solving, the last piece is auto focusing…..
Auto focusing – the final piece of the jigsaw!
So…. I bought another arduino, this time a mini one, and got a good friend to build a little plate to allow a stepper motor to be mounted on my focuser, I then connected it to the Arduino and installed the SGL Focus Software – this worked a treat, more or less straight out the box! I had to hard code the speed into it but other than that it allowed me to focus from my laptop, although…… I really wanted this automated too, so I downloaded FocusMax and after much messing about with it’s settings (Its not the easiest to understand, and I think it was more by luck than anything else that I eventually got it working) I now have auto focusing working!!!
So… the workflow is now….
Use VNC to remote into the observatory from the warmth of the house 🙂
Power on the Telescope and CCD
Connect to the Telescope
Click the button on my app to open the roof and unpark
Start CCD Commander
enter the co-ords of a star to focus on
goto star and plate solve
focus on star
find guide star and start guiding
Well… I want to redo the app, in fact I am in the middle of it now – basically it works but is not written well. As a training exercise I am rewriting it properly! I will also control a red light in the scope room and a white light in the observatory warm room, I also have a rain sensor that I need to wire up as well. Finally, I would really like to try some fancy stuff, have it send me a text message if a guide star is lost or if it starts to rain – but all thats really a job for next year I think!
I got the Observatory re-plasterboarded as the job I did originally left a little to be desired……. I thought I would post up a couple of piccies of it and the kit as I think the only Obsy pictures were when it was getting built!
I also managed to get hold of an EQ6 Pro for a cracking price so that is now permanently mounted and the HEQ5 Pro I used to have is now a grab ‘n go mount – I can finally leave everything setup and go to some of the local meets that scottishastronomers.com have from time to time 🙂
It’s seems that I rather overdid the silicone on the mirror last time I did this and it may have been contributing to triangular stars due to the mirror being a little pinched in the cell. I’m not 100% convinced but the general opinion was that all is needed is 3 pads of silicone for the mirror to sit on – not, as I had previously, the whole cell being covered in silicone!
Anyway, tonight I set about removing the old stuff and replacing it was said ‘blobs’……. Getting the stuff off was not too bad, got a craft knife set for £1 (from Poundland, of course!) and it worked a treat, I sliced thought the old stuff, removed the mirror, then used a flat edged blade and it just came right off the mirror when slid under the remaining silicone – All in all it took about an hour to get it back to ‘normal’
So above you can see the mirror cell and the 3 cork spacers it previously sat on, this is where the silicone blobs will go….
Next was to work out how to create a little space between the cell and mirror so that when placing it on the silicone pads it would not just squash them and sit back on the mirror cell itself. After pondering for quite a while about what to use to create this spacer I glanced upon the rubber mirror clips – these are like a little L shaped piece of rubber, so now there is 3 little spacers and the mirror sitting drying on to the 3 blobs of clear silicone. When it’s dry in 24hrs time, I will remove the spacers and stick them back on the mirror (I had actually done away with them when I had previously siliconed the mirror to the cell but think that as I now only have 3 blobs of silicone, it’s best to have them back in for safety!). The only (slight) concern is that the mirror is now sitting higher in the cell than it was before and does not have as much lateral support, I have slid 3 cardboard spacers in beside the cork spacers to tighten then up but am wondering whether to place a further 3 blobs of silicone to give more lateral support to the mirror????
Above, the mirror cell with the silicone ‘blobs, also shown is the rubber spacers (aka mirror clips)
The mirror back in the cell, you can also see the cork spacers for lateral support – not decided whether to add silicone here or not…
A couple of other potential areas for problems were also addressed as part of tonight’s re-silicone….
First up, the length of the collimation screws
The collimation screws supplied are just a bit too long and if tightened right up will actually touch the mirror surface, pushing the mirror forwards in the cell and further up against the mirror clips. Too tight mirror clips cause triangular stars, that’s bad enough but having a metal screw touching my glass mirror, something had to be done! I bought a pack of washers and added 4 to each screw, now when in as tight as they go, they still don’t touch the mirror – Job done! (BTW, the springs supplied with this scope are inadequate, I have already replaced them with stronger ones from ‘Bob’s Knobs’)
Finally, the centre spot – I have heard from a few people that the centre spot was not erm… centre! I found a cake tin exactly the same size as the mirror, drew round it on to a sheet of A4 paper and cut it out, folded it in half, then half again and cut a little from the centre to make a circle. I placed this on top of the mirror and it seems that my spot is, spot on!
Checking out the centre spot position
So… Now I just need to wait on it drying and then re-collimate and hopefully I will have some nice round stars!
After re-doing the collimation twice I think I have just about cracked it! Here is a 10sec 100% crop of Aldebaran
Been having problems keeping my GSO F4 in collimation due to the mirror moving about a bit (It’s the Altiar Optics F4 version). I had previously tightened the mirror clips and although this helped collimation it was still far from perfect when flipping from Horizontal to vertical and this was visible in images. I have now taken the bulls by the horn and decided to silicon (the clear type) the mirror to the support cell.
After 48hrs the silicon has set and I have to say that so far (No star test yet!) the collimation appears to be a lot better. When using the laser collimator there is now hardly and movement from horizontal to vertical, whereas before the laser spot would slowly wander over the face of the colimator.
Here’s some pictures of the setup:
Looks like the silicon has done the trick, the collimation seems to be holding really well, below is a single shot at 100% crop – looks pretty good to me!
I have decided that I dont get on with my SCT imaging wise – the stars are always blobby with horrible colour and the vignetting was driving me nuts! So….. I have now got hold of an 8″ F4 Imaging Newtonian from Altair Optics. It’s not perfect – the collimation is a nightmare, the focuser needs replaced as it’s horrible BUT, the stars are not bad with the limited collimation and the colours are really nice, so it’s a keeper……. So far!
This is the first real image from it, I had a couple of false starts and the collimation is a nightmare, I had to find the target and then collimate when I was on target, hence the need for a new focuser! The image is a stack of 2 min subs, making a total of 1hr 58mins of integrated exposure.
Anyway here is M13 – the great globular cluster in Hercules. Globular clusters are massive collections of gravitationally bound stars at the very edge of the galaxy, one theory is that these are failed galaxies. There are over 300,000 stars in this cluster, it can be seen easily with smaller amateur instruments as a small fuzzy ball, with 4.5″ scopes starting to be able to resolve a few individual stars.
When taking images a few days ago of M45 with my QHY8 through an 8″ SCT I noticed these weird reflections
Well, I did more testing and asked a question over on Stargazerslounge (http://stargazerslounge.com/imaging-discussion/121558-whats-2.html#post1606567) . It seemed it was a reflection from another piece of glass in the imaging train. After taking another image (see Below) I know think this is either the Focal Reducer or the Light Pollution filter. I am waiting on a T Thread LPR Filter so that I can simply remove the QHY8 Infra Red filter and replace with the T Thread one. This will mean that I can remove the SCT > 2″ Adapter and existing LPR Filter as well as a 2″ > SCT adapter before the reducer. At the moment I have a 2″ LPR and because of this I need these SCT>2″ FILTER then 2″ Back to SCT adapter. Hopefully by removing the filter from the front of the train and moving it back it will resolve the problem. The image below shows Jupiter (and some moons) in focus and you can just about make out the reflection of the Bahtinoff Focussing mask (http://www.nightskyimages.co.uk/bahtinov_mask.htm) that sits over the front of the corrector plate to aid focussing – I think the fact that the mask can be seen out of focus indicates that something nearer to the scope is causing the reflections. You may need to copy the image and look at it in another image application to see the reflection but on my laptop if I look carefully I can see it.