I’ve been thinking about getting another OTA to enable me to image at a higher magnification, but been a little worried about whether my mount and guide setup would support it. A few weeks back an old blue tube Skywatcher 200p OTA appeared on the SGL classified section for £50- it felt like a low risk way to find out.
As advertised, the tube has a few cosmetic marks, but the optics all seem to be good. Despite the impending Storm Gareth I really wanted to give it a go last night and see what how it would work. Collimation, balance and focus was easy enough (even though the focuser is a bit sticky), but the semi-cloudy conditions and the gusting winds causing the scope to jump around persuaded me to stick to the moon for my first effort.
Of the pictures below, the full disk is from my 600d with a 0.9 coma corrector; whilst the others are from stacked avi’s on my ZWO Barlowed to x3.2 with a bit of wavelet adjustment in Registax (I wrote that like I know what I’m doing in Registax, which I really don’t!). Finally there’s a little picture of the scope in action to record the moment!
A touch of lurgy at the moment has given me an opportunity to catch up on some imaging processing. The cone was the trickier of the pair- it’s much less bright and because there’s lots of gas around it, finding some background to calibrate on was not easy. Also, in my efforts to strip light pollution (both moon and LED) from the RGB subs I’ve removed any Oiii signal which I know is present somewhere in this! California was easier as it has higher surface brightness.
14/2/19: Ha – 14x 10 min subs (yes- my wife is very understanding)
On Monday night, with a very bright moon I took some Ha shots. M42 can be quite a tricky target because there’s such a difference in brightness between the centre and outlying areas, so this is a mix of 1 and 10 min exposures with the Ha filter. Unfortunately the clouds were rolling over quite frequently, and of 15 10 mins shots, only 3 were actually usable- this has given me a very noisy Ha channel to work with.
I had a bit more luck on Thursday night, before the moon came up, capturing 1 and 5 min exposures with the IDAS filter that I use to suppress the bright LED lights. Merging mixed exposure times is a new technique for me, so I’m quite pleased with how it has come out. The trapezium can’t quite be seen, but there’s still a reasonable amount of detail in the bright sections that surround it. The hardest bit was reducing the noise in the final colour image- I’ve lost a bit of detail doing this. Ah well- gives me something to aim for next year…
Finally had a chance to process the remaining images from the little clear spell we had last week.
It unfortunately conincided with work and other commitments so I’m really missing observing at the moment- but playing with the images has been some nice astro therapy in its absence.
Rosette HaRGB – this is the colour version of one I posted on 17th January- I managed to get 80 minutes of RGB on the 30th to add to the Ha pictures I’d taken earlier in the month. I really like this object- it’s a nice cluster in the dob and I can just about see some of the nebulosity (although obviously not the Ha). I think this image is a bit unbalanced- the red rightly dominates, but there shuold be some lighter colour as well around the centre. Probably because that’s the narrowband filter I’ve used, and it had 10 min exposures vs only 5 for the rest of the spectrum. I’d like to have another go at this and see if I can bring out some of the other colours. I also hadn’t understood how big this is-it’s three times the size of the Orion nebula and I love the way you can see how the newly formed stars have blown bubbles in the gaseous structure. There’s a range of distances from different sources- but they seem to average about 5000 light years- so this light started travelling when they were building Stonehenge.
Alnitak/Flame/Horsehead – I’m often drawn to this one- I find the Horsehead such a charismatic object. I’ve looked for it lots of times when the skies seem to be transparent but never succeeded in spotting it visually. The black and white image is another Ha effort- this time from 2nd February. The RGB bit was from a couple of nights before, and was one that I set running after an evening in the pub. It’s a much tighter crop than I would have liked because my framing was, shall we say, “not optimal”. I think I prefer the monochrome version of this.
This picture below was after the the Ha mage. I left it imaging overnight whilst we had guests and went back to it in the morning with the mount still faithfully tracking the constellation somewhere over America, but with the guiding not working so well! If you ever doubted the heat that cameras can put out- look at how everything but the guide camera is iced up.
This astronomy lark seems to be feast or famine; after a few weeks of clouds we suddenly get 2 nights with clear skies! Great to read about others experiences. I had a really enjoyable observing session on Sunday night, plus over Sunday and Monday I was able to image the Rosette (RGB to add to the Ha from a couple of weeks ago), the Soul nebula and Pacman.
Despite getting 3 hours of exposures on the Soul Nebula (I left the camera running overnight and also managed to get 3 hours of pictures of the shed wall!) the initial stack looks like it’s going to be disappointing so I’ve had a go at Pacman instead.
45 mins of guided 5 min subs before the clouds rolled in on Monday night!
Always a bit tricky imaging under a bright moon, but even more so when you’re in clumsy mode. Last night I managed to disconnect the power from my mount whilst aligning. Twice! Then I dropped an eyepiece by slewing the scope without having it fixed properly (fortunately it landed on the rubber eye cup). Finally I spent ages trying to work out why I couldn’t focus my guide-scope until the penny finally dropped that I was twiddling with the locking ring and not the focuser. So I’m taking this picture as a victory of the scope over its owner!
15x 10 min subs – Canon 600d – 130 pd-s- 7nm Ha filter.
The one upside of the last few weeks abysmal lack of astro friendly weather is that I’ve finally had the opportunity to put together the time-lapse videos from my shed project. OK- It’s only 5 minutes with the help of time-lapse video- but it was quite a quick build when I actually got the chance to work on it.
One evening last May there was a unanimous perfect forecast from different weather apps and I dutifully set all the gear up for some imaging. Just as we were getting to darkness a thick bank of cloud rolled in. As it was not forecast, I decided to hang on for the sky to clear, and instead spent the next hour looking round the garden working out how I could have a more permanent set up with all of the advantages it gives. And no- the sky didn’t clear that night…
Looking about the internet there are some amazing creations- both home-made and purchased- but these were all well beyond my available resources for this project in either time or money. Besides keeping costs down, I wanted the following:
– Really small footprint.
– I didn’t want it to look like an observatory (which is much too grand a word anyway for this shed).
– If I wanted to bring my mount out to a club evening or dark site, I didn’t want it to be any more hassle than taking the mount and scope out of the garage is.
– I used an 7’x5’ apex shed design. This has the disadvantage of limiting the view where the apexes are- but my views are restricted in those directions anyway- and with the smaller roof panels I can move them manually and drop them down the side walls.
– Upside-down guttering is used to seal the gap at the top between the panels.
– No pier- the tripod sits on bricks that come through the shed floor so I don’t cause vibrations when I’m walking around.
– The roof panels slide off on fixed castors fitted to the shed walls (although in practice the tower bolts catch on the sides and it’s more of a lift than a slide).
– The electrics are in a ventilated plastic storage box to keep them away from moisture. I run an outdoor cable from the garage when it’s in use. I’m using a Nevada power supply which has been a lot less hassle than using a battery, and I can’t prove it, but I think the mount is running better.
Overall, I’m pretty pleased with it- it only takes a couple of minutes to open the roof, the polar alignment seems to be pretty much spot on each time I check it (despite not having a pier) and my setup time to when I start the first sub has dropped from an hour to around twenty minutes or so. Most of this time is to align, frame and focus.
The shed came from Tiger Sheds and seems to be of reasonable quality. The weight of the roof panels was heavier than I had expected (when I was checking out the design I didn’t allow for the weight of the roof felt- blimey it’s heavy!!!) and I was thinking about ways to overcome this. But I’ve got used to the technique to move the panels, and it has stood up really well to some very wet and windy weather over the last few weeks. For now I’m inclined to leave it as it is. It’s also pretty snug in there. I never intended to use it for observing, but if I ever changed my mind about that I’d probably need to start again because space around the scope is pretty limited and alignment often involves a short stepladder and hanging off walls…
It will just about take a 1200mm Newt OTA, but with that one it is really cosy.
It isn’t quite finished yet- I’m in the process of adding some shelving, I need to improve the ventilation (I’m looking into solar powered fans, but failing that I’ll just put some vents in) and I need to lag the walls to help keep the temperature more stable.
So, if anyone is thinking about a more permanent setup, but is concerned about the cost and effort involved, it needn’t be an architectural masterpiece. The basic shed was £320 and with the materials for the base and other odds and sods I’m probably a little north of £500 for the whole project. Which will hopefully allow me to be a little more spontaneous with imaging. Or at least have wasted less time when ‘secret’ clouds come rolling in…
Hope you enjoy the video (speaking of which- this was partly put together with Videopad as recommended at a RAG meeting earlier in the year- I can second that recommendation! 😊).
Slightly strange conditions last night- the sky south and east was distinctly murky with very ropey seeing. This isn’t unusual as I live north and west of Burton, but it seemed to be especially exaggerated. List below was all in 14” dob:
Aldeberan and the Hyades– whilst checking the Finder and the Rigel were lined up properly I put Aldeberan in the EP. It’s too easy to forget the simple pleasure of putting a big fat red star with whopping diffraction spikes (yeah, I know- not everyone’s cup of tea) in the middle of your field of view. Spent a while wandering round the neighbouring star field. A lovely start and almost forgot I had a list to go through.
Comet 46p – A nice little hop from Epsilon Taurus, but still took a couple of attempts. The head was really clear; I spent ages trying to see the tail. Eventually, with the 35mm in, a bit of averted vision and wiggling the scope I could see some elongation of the head and a hint of the tail.
Pleiades – Because if you’re in the area with a low power eyepiece it’s rude not to.
Mars – shrinking after the summer, but some detail still visible at 206x including polar cap.
Neptune – very small, but the blue colour is so striking. Given the seeing so low in the sky I didn’t try to go past 206x
NGC 6543 – Cat’s eye nebula – lovely pleasing green, and decent disk at 206x
NGC 7023 – Iris Cluster and Nebula – I got to the cluster OK, and I think I found some nebulosity but it was very faint. Not really sure.
NGC6946 – Fireworks Galaxy – Very faint and averted vision only.
NGC7331 and Stephan’s Quintet (NGC7320) – I’ve wanted to have a go at this one for a while, and with it high in a good part of the sky it seemed like a good chance. NGC7331 was straightforward- with an elongated shape clearly visible with direct vision. At low power (47x) it was easy to put it in same the FOV as Stephan’s Quintet. The four stars that they sit within were a distinctive shape and easily picked out. I think when you know what something is supposed to look like it’s easy to imagine it right there. There could possibly, maybe, have been a sort of mottling in the right area with averted vision??? I don’t think I can really claim that.
M42 – Again- rude not to and wonderful as always. The seeing was bad around there, although there was a hint of the ‘E’ star in the trapezium. Spent a while playing with Oiii and UHC filters. The Oiii filter just gives a brilliant view of the cloud with so much texture.
Rosette Nebula – My first observation of this object. The central cluster was easily picked out and I could find some faint nebulosity, especially beneath and to the right of the cluster.
Really enjoyable evening, and hopefully have some subs of 46p to play with soon…
Seem to constantly be a few nights behind at the moment- but here’s Monday night’s effort on the M52 cluster and the Bubble nebula in Cassiopeia. It’s just RGB with the light pollution filter- 20x 5 min subs plus darks, flats and bias.