Having just got back from the Kelling Heath star party I would normally be processing images taken there. The weather for the event this spring didn’t co-operate though so while we still had a great trip the actual astronomy time was zero.
So it’s back to an image I took with Dan on the 20″ last sunday of M104. I’m having real trouble adding the colour into this image so while I struggle with that here’s the luminance frames.
Frames: 30x 30 seconds
Bin: 2×2
Galaxy clusters are amongst the largest structures in the observable universe. Local clusters include the Local Group (including the Milky Way and Andromeda galaxies), the M81 group (11 million light years), M101 group (24 million light years) and Virgo Cluster (65 million light years).
Rather further away is the Abell 2065 cluster which is somewhere between 1 and 1.5 billion light years away and located in the constellation Corona Borealis. With the exception of a sprinkling of bright foreground stars most of the objects in this image are galaxies with the brightest members a diminutive magnitude 16.5.
This image is a stack of 10 1 minute exposure on the 20″ taken with the Atik 383L.
Some night sky objects are truely huge. The problem is that they’re hard to observe as their surface brightness is low and they require a large wide field telescope and a very dark sky to actually eyeball them. One such object is Sharpless 220, a.k.a. NGC 1499, a.k.a. The California Nebula in Perseus. This extends almost 2.5 degrees, or about 3 moon widths.
This picture was taken with a Canon 75-300mm zoom lens mounted on my QHY9C. Focal length was 135mm providing a 7.7 x 5.7 degree field. 12 5 minute exposures were combined and the light pollution gradient removed with GradientXterminator.
This week has been a surprise with clear nights and no moon, albeit rather hazy. Having missed sunday evening, monday evening took a while to clear and Auriga was getting rather low by the time I started imaging. However, before it dropped into the haze I got 30 minutes worth of the area around IC405 and IC410 using 3 minute exposures.
The next opportunity was on wednesday and with the skies clearing earlier in the evening I added another 90 minutes of exposures. It helps that the central cluster is so bright which makes centring the image easier.
One image had a satellite trail so here’s the result of stacking the remaining 44 frames.
Telescope: WO Zenithstar 70 with FFIII
Camera: QHY9C
Mount: Astrotrac
Despite a bright moon in the sky last night I was determined to take some images using my QHY9C on the 20″. Things didn’t go exactly to plan and I had some difficulties with guiding; mainly loss of guide star which I put down to some thin, high cloud. To eliminate other effects I slewed to a nearly bright star to see if I could actually guide on anything.
With the SBIG STV producing 26K ADU, Diadem in Coma Berenices at Mag 4.32 provided a good target and guided nicely while I took several 1 minute exposures. After stacking I noticed a faint object near to the star and loaded the image into Aladin (http://aladin.u-strasbg.fr/aladin.gml) to identify it. The NASA/IPAC Extragalactic Database (NED) provided a name, KUG 1308+178 and some basic details: Spiral galaxy, Magnitude 16.5, major diameter 0.4′, minor diameter 0.2′.
Other images of this galaxy are few and far between but I did find one taken on the Palomar 48-inch Schmidt in 1950.
I purchased yet another T2 extension tube at AstroFest, this time a 7mm one. Finally, I can get to focus on the Sigma 10-20mm zoom with the QHY9 camera. It may indicate 0.6m on the lens scale but I’m not worried about that.
I set it on 20mm for some wide field pictures of Orion with 300 second exposures at f/3.5. The cropped result is shown here after some use of GradientXterminator to remove some of the light pollution in the frame.
There’s some pretty bad spherical aberration with this lens but that can be expected with such a short focal length.
Sunday night was going to be a wide-field night using my Sigma 10-20mm zoom attached to the QHY camera. Things didn’t go to plan. The issue was focusing again. I’d cracked this on the 75-300 zoom but the Sigma is very fussy about back focus. A 10mm extension tube put the focus point beyond infinity and a 5mm tube was equally unsuitable at the other end of the focus range. So, I need something between the two but ideally it needs to be adjustable as well. Back to the drawing board.
With that plan axed for the night I put the Zenithstar 70mm on the mount and in the time remaining before Orion disappeared behind a tree took 90 minutes worth of 3 minute exposures of the region around Alnitak.
Monday evening was the clearest of the year so I put the Zenithstar on the Astrotrac with the QHY9C and pointed it towards the Rosette nebula. The central cluster was an easy binocular object and using the red-dot finder the telescope was pointed without difficulty.
While the polar alignment looked reasonably accurate there was some drift in RA that I will need to eliminate. Cable drag is one possibility I’ve looked at before but I suspect that the Astrotrac is tracking at the wrong rate and may require recalibration.
Trailing was quite pronounced on 5 minute exposures but I took 19 images of this length.
With the purchase of an additional 15mm extension tube I was ready for a clear night and Sunday night delivered. I got the 9.25″ setup on the CG-5 relatively quickly and found that with the additional tube both cameras were able to focus. M78 is something I’ve wanted to image for a while so after aligning the mount a goto put the twin stars of the nebula in the field of view.
The big problem was finding a guide star in this region. I found that putting a wide field eyepiece in for an initial look is a good time saver and, having found a star I replaced the camera and set it for 2 second exposures for guiding with PHD.
Initial attempts at 5 minute exposures were unsuccessful so I dropped these to 3 minutes and set the QHY running for 2 hours worth. Despite some fairly erratic guiding graphs I was surprised at the quality of the images and only had to throw 2 for non-round stars and one for a satellite trail.
M78 is part of a larger nebula complex in Orion with M42/43 the most prominent component. It is the only principle reflection nebula in the Messier catalog. McNeil’s variable nebula is bright and visible towards the top right of the image.
For another reflection nebula, check Dan’s post here: http://farawaythings.blogspot.com/2011/12/perseus-cloud.html
One of the things I’ve been planning to do for some time is getting an auto-guider working with the club CG-5 mount. I had plans for the old Starlight-Xpress camera but it’s just to heavy for the off-axis guider to support. The purchase of an Imaging Source camera by the club has re-opened the possibilities here.
A clear, moonlit night provided a perfect opportunity to get this setup and I put the Celestron 9.25″ on the mount with the guide camera and my QHY-9C hanging off the radial guider on the back. What became clear pretty quickly was that I couldn’t get both cameras into focus at the same time. I was short of about 15mm of T2 tube on the QHY. The rest of the testing appeared to run OK though so I’ll just need to obtain a new extension tube before I can try again.
As I’m always reluctant to pack up without imaging anything I turned the telescope towards M42 in Orion for some 30 second unguided frames. 10 were stacked and processed for this picture.
More light required!