Mike JW

Lovely when you can capture 3 Arps in one shot. High resolution images seem to show obvious small, bright companions on the arm for 48 and 88. I think you have captured them but a longer focal length set up might make them more obvious. http://cseligman.com/text/atlas/pgc04a.htm#pgc4789 - worth a look at this link for Arp 48. Mike

Recently I too took a look at Arp 65 with the C11 - the fov being much smaller than Martin's set up. However the increased aperture enabled some of the tidal tail that goes to companion 1 to be picked up. I think also I have a hint of companion 3 and a definite for companion 2 Mike

THIS THREAD IS DEVOTED TO EEVA OBSERVATIONS OF THE SHK COMPACT GALAXY GROUPS - enjoy the journey. In 1957 Shakhabazian noted on the Palomar Sky Atlas a group of 17 red stellar like objects clustered within 1 arc minute. It was thought they were a cluster of red stars. Later analysis (1972) showed them to be galaxies. This group then became known as Shakhabazian 1 (SHK 1). In 1973 a systematic search of the Palomar Sky Survey plates revealed more groups – compact groups of compact galaxies (CCCG). There are 377 groups. Being compact then their gravitational forces at play within the groups, are heating up interstellar gas, twisting some of the galaxies. There are three broad categories spherical, chains and peripheric (on the edge of the area). There are some which do not fit into these three categories. They are true groups and lie beyond our local super-cluster. Many groups have strong radio sources. The criteria for the groups are as follows: The groups consist of 5 to 15 members. The apparent magnitude of the individual galaxies is between 14 and 19 mag. The groups are compact, i.e., the distances between galaxies are only 3-5 times the diameters of galaxies. Nearly all member galaxies are extremely red, with at most 1-2 blue galaxies in a group. Members of groups are compact (relatively high surface brightness, borders not diffuse). The groups are isolated. ShCGs were originally called compact groups of compact galaxies because the images of most of the constituent galaxies in these groups seemed very compact. Later observations of these groups with high angular resolution revealed that member galaxies are mostly of E and S0 types. Also it has now been shown that the group members are not particularly compact so the more recent papers now call them Shakhbazian Compact Galaxy Groups (SCGGs) or SHKs. Red shifts for these groups are slowly being determined – about 70 groups so far. RESOURCES - a list in excel format. Shakhbazian Galaxy Groups.xlsx Mike and Martin

Hi Martin, As always with the SHKs they have an element of intrigue as so little is known about them. NED has no magnitude info for two of the chain, the other 3 are mag 18 with one at mag 18.9. To the right of the chain your red circle goes through another galaxy - only info is it is an infra red source. The separate northern member has no information. The tiny chain you label as anon - two are Infra sources, the third is an ultra violet source. No other info. IC 1542 - love your description. Like you I cannot find any info other than Spiral? That seems a totally inadequate designation. However NED shows two galaxies and a Ultra violet source at this point. Now this does make some sense because the "mess" would suggest at least two galaxies interacting (NED redshift info is very similar for the two galaxies). Mike

Hi Brian, Cameras are a mystery to me - point and shoot is about my limit, although I have looked into pixel size versus focal length but I will leave others to advise. Below is a some shots from my early days of using a C9.25 to help you gauge what you can achieve. Now with more experience and using Jocular software. I could do much better I was still trying to get use to the SLL software so there are some odd labels. I have used the C9 at F5 (using a 0.5 focal reducer). No need to be concerned about field rotation - the software deals with that. Focusing is a doddle with a Bahtinov Mask - absolutely essential. Mike

Hi Brian, In some ways what ever works for you, then go for it. I took a look at the link - wonderful images. To me though they would not appear to be in the spirit of EEVA - which is about observing using the EEVA technique, rather than producing wonderful images and no additional comments re the observation, links to research papers..... Of course EEVA is imaging but at the risk of being boring, it about a technique that aids observing rather than producing yet another fine image of the well known objects. At the most I will take a "live" stack and drop it into Photoshop, just to tweak it a bit - spend no more than a couple of minutes doing that. Imaging as we know involves much post processing with the emphasis on the techniques rather than the object. If a camera gets invented that can give a "live" image in the space of max 5 minutes at the level of clarity/colour/detail as per many a wonderful image then I would certainly go for it but still with the thought of observing rather than imaging. Others will have a different view, which makes for much interest. Which ever pathway you decide, enjoy it. Mike

Thanks Vlaiv - makes me wonder about pointing one of my scopes at Mayall 11 again but his time use 1x1 and not binning and to keep the subs very short. Mike

Hi Paul, I have just been playing with the download in Photoshop Elements. It would not appear to be a star. If I did not know that the scope was pointing in the Andromeda galaxy region, then I would say it was a galaxy but equally it could be as Martin suggests a badly out of focus (bright) star. Mike

Hi PCW, I very much doubt it is Mayall 11. See below. It took some careful alignment, then syncing to UGC 330 before going for the globular. Mike

Hi, nothing like a little who can see the faintest galaxy competition!!!! Fairly certain I can see PGC 2035682 at mag 17.9 and PGC 2035566 at mag 18.1 - mag 18 using a 9.25" scope and in 10 minutes - impressive. Also checked the single 20 second shot of NGC 1268 - definite mag 17.0 galaxy PGC 2183808 - wonderful. Makes me want to rush out and get a Hyperstar for the C11, until I look at the price............ Mike

There is much to absorb in the shot. 517 is VV36, 507 is VV 207. The faintest galaxy I have checked is mag 16.6 but there looks like other fuzz spots that are fainter. Mike

Yep - put the thread here in EEVA as we are regularly going deep. Mike

Thanks Martin, it would be good to point the 15 at it but it is too low for the Dob. Interesting article - much to learn as always. Cheers, Mike PS. Below is a screen shot from an article https://core.ac.uk/download/pdf/33108853.pdf Shows the anatomy of the pairing - a tail, a bridge and a clumpy plume. The stars in the bridge are thought to be new stars formed by the tidal interaction as the northern galaxy passed by. It appears that there are not any stars in the bridge that have been pulled out of the galaxies.

Last night I wandered through the Arps in Aquarius. I finished on Arp 295. I knew they had a long connecting filament but also knew I would have to go beyond my customary 5 minute total time. I decided to let it run whilst I began clearing away the chaos of an observing session and walked around to warm up my shivering body. Arp 295 is a Zwicky Pair. Both are spirals and are about 285 million lyrs away. The lower one looks like it has small dwarf galaxies at each end - it doesn't. To the right of this galaxy are three dwarf galaxies in a line at a similar distance. I picked up the obvious first galaxy, hint of the second. Other galaxies in the shot are also around the 280 million lyrs away. To my delight and amazement I actually picked up a hint of the filament linking the two and the brighter filament heading down (south) from the lower galaxy. Looks like the corrector plate needs a dust off/clean. Hard to find the best settings because this crowd are low down in the murk here in GB. Mike

Wonderful to see such a wide fov with all those galaxies. Amazed at what just 20 seconds picks up. I get so use to a narrow fov, so seeing this shot gives the context of this galaxy group. Thanks Tony (and to Martin for suggesting the group). Mike

Hi Tony, Great to know you have the spacing sorted and to show the power of the EEVA technique. Noting you are using the hyperstar I would be interested to see what results are possible in a shorter total exposure time. Looking forward to your next posts. Mike

8/10/20. My attempt from last night using the 15. A little bit more detail but not significantly more. Achieved quicker of course with that amount of aperture. Tweaked a bit in photoshop. Mike

Hi Martin, When looking at NGC 183 visually little did I realise what lurked near by. I saw the chain straight away and great to ponder if the galaxies lie within a filament connecting the super-clusters. I have looked at the article you mention - page 9 - lower diagram would suggest this is not the case from the RA/DEC data? but looking at other articles then it could well be. As you say the distance is in the right region. Apparently the Perseus -Pegasus filament you mention lies next to the Pisces - Cetus filament (1 billion x 150 million lyrs) and includes the Virgo super-cluster. Of course the reality gets very complex - this article looks at the Perseus end -https://iopscience.iop.org/article/10.1086/301196/fulltext/ - and see image below showing the main cluster filament and also various minor filaments. The dots are galaxy plots. http://egg.astro.cornell.edu/alfalfa/ugradteam/uat16talks/uat16_introAPPSS.pdf - a very interesting power point which includes references to the filament. Mike

Hi Martin, I love this group and a pity I lost my original image of this Arp. Also well remember squinting in the 20 to see these galaxies and great to see your shot and as you indicate there is much to absorb in this group. Mike

Cannot wait to have a look myself. Beautiful pairing and as you indicate, much detail to be enjoyed. Known as the Taffy Galaxies. With the obvious ring I wonder if it should be classified as SBc (r) . Quite few articles on this pairing. Mike http://adsabs.harvard.edu/full/1993AJ....105.1730C https://iopscience.iop.org/article/10.3847/1538-4357/aaac2c

Hi BL, I am not sure what you are really asking. As you know the Lodestar will slide into the standard visual back of the C11. Thus if you are wishing to use the scope at its native F10 then slide the lodestar in and focus....... However the lower the f ratio used on a scope the quicker a decent image will be obtained. Standard set up for a SCT scope such as the C11 (or C9, C8...) is to use the Celestron f6.3 reducer on the back of the scope, then the visual back, then the lodestar. The distance of the lodestar chip from the back of the reducer needs to be 100 - 105 mm to get the best position. Feel free to come back with more questions. Mike

Martin, you are right. Exposures are a max of just 0.5 subs. At this speed Sharpcap dropped many of them but the technique is doable - can't say it would appeal. The view of M57 is sort of what one would see direct visual anyway but with much more effort and less pleasing. Interesting to read how they manged it. Mike

and me for Baader Wonder Fluid. I take Martin's approach (as does Bill) - keep it simple so that you can concentrate on observing rather than getting bogged down in complications. I used a C9.25 for a year or so (its now a C11). The C9.25 is optically very good and personally I think is an excellent EEVA scope. Its decent aperture gets quick results but can go deep. At f6.3 it has sufficient wide fov to encompass some really lovely galaxy groups and nebulae but good to for picking up smaller DSO targets. (If I could have just one scope for EEVA it would be the C9.25 - aperture fever struck and hence the C11). I did try the scope at f5 but vignetting would kick in so plan on using it at f6.3. With the f6.3 reducer I leave it in all the time so I can do visual then easily swop to camera and back again. Hyperstar - great for wide fov and quick results but would you plan to leave it always in place - that keeps it simple but then if you wish to do a spot of visual then it would be a pain taking it out etc. Whereas with the reducer in place with the C9.25 I could grab and go for a quick lunar outing or some lovely doubles/conjunction and then as stated go over to the camera. Absolutely no need to guide with EEVA - I use a Dob at times (obviously ALT/AZ). Focusing is critical - use a Bahtinov mask - so easy and accurate and quick. In my opinion there is not a camera that is excellent for both DSOs and planetary using the EEVA technique. (others may disagree?). Why get a camera for the planets at the moment? Mars is passing opposition. Jupiter and Saturn will continue to be low down for several years yet so always in rubbish air. So my opinion would be to get a camera that would do well for you on DSOs - there are thousands of objects. Take a browse through the posts in the EEVA reports sections - there is a lifetime of possibilities up there. With my former C9 I used the Starlight Express Lodestar x2 mono and also the ultrastar. With the C11 I use just the ultrastar as it has a bigger chip and thus wider fov. Personally I prefer the ultrastar - smaller pixel size and a bigger chip. I don't do planets (as in bright planets - fun doing Uranus, Neptune and Pluto with it). Mono cameras are more sensitive than colour and thus you get a result quicker. Sometimes I think about going colour but that is another layer of complication. Good luck and have fun, Mike

Hi Ken, Like Martin I use a CCD camera. I use the Ultrastar camera/starlight live software combination and use the Jocular software to produce my "live images". This combination works very well. Take a look through the EEVA forum to view the various posts and get a feel for what set ups folk are using. Cheers Mike

You really need a scope that is driven. Mike