mdstuart

Planetman 18mm. It all works fine and is strong enough etc but if they were wider it would make it easier to embed rollers rather than just using the normal Teflon pads. At some point I might make a new rocker box and bearings with thicker walls. Mark

Will follow with interest. I put a 20 inch together recently. With hindsight I would have gone for thicker bearings to allow for rollers. I would go for different top connectors as I had to brace mine. However my dob now works well even though its not perfect. Mark

Quite pleased with this picture of my dob taken with my new Samsung phone after this evenings galaxy observing.

If you mask down a dob the star bloat can be made to dissappear.. Mark

Today I have been looking through the NASA Atlas of galaxies. It lists galaxies in red shift order. I found out that I have only seen 3 of the first 10. Some are southern objects and some have a low surface brightness but I might try this one. NGC 4395 in CVN. Do others find targets when reading? Mark

Well done Hutch star or finding that black eye galaxy, I always find it hard to hop too. The needle galaxy is much fainter but a lovely sight with that star next to its central core. Saganite - I have that book as well and used it last night to try to spot ARP105 but failed - see below. A NIGHT OF OBSERVING GALAXIES ON A COLD CLEAR NIGHT WITH THE 20 INCH DOB So I set up which took about 15mins, put on lots of layers of clothing and was out by 8.30pm. Looked clear, a bit murky to the SW. Just a check for the cirrus ahead of the atlantic fronts but nothing evident so we proceed. The first object can be harder as my eyes have not yet adjusted but NGC 3517 was not too hard to pick out with averted vision. Discovered in 1793 by William Hershel...yes 1793 is that not amazing to think about..this is a face on spiral about 350 million light years away so a long way out! Very pleased with that. m13.8 in the blue spectrum and a surface brightness of 22.4. A later check indicated I had seen a mag 15.0 star so the skies are transparent at the moment. No I could not see the companion in this image! Ten minutes later I am on NGC 3530. This was brighter, I can see it in my 16mm eyepiece! Turns out this is a lot closer at 80 million light years and is one of the group of 133 galaxies including M51/M106 etc. Next was UGC 6534. Very different again. Low surface brightness slither that was pretty tough to see. The skies are not quite as good now with a limiting magnitude at the eyepiece of 14.5. On to NGC 4081.....wow a fine double star next to the galaxy, Nick you need to look at this. Two white stars sharp as full stops showing a steady sky. The galaxy is part of the same group as NGC 3530 seen earlier and Dreyer notes the double nearby so I am discovering a fine sight seen back in the day as my son would say. NGC 3648 is next, its now 9.25pm. This was almost stellar to me and visible with direct vision. The image below is very different to what I saw as it shows the halo. I think I only saw the core. Dreyer says perhaps a double star...yes I can see why he wrote that. The galaxy is part of a group of four apparently including NGC 3665 / NGC 3658 and NGC 3652 all of which I saw with my trusty old 10 inch dob many years back so now I have the set On to NGC 3694. Another one visible with direct vision tonight. Looking at the image I am only seeing the centre of this galaxy about 100 million light years away and it is in starburst mode which may explain how bright it is. The galaxy sits in a very isolated star field which makes it harder to locate. Again this one is part of a small group including NGC 3755/NGC 3813, Markarian 1301 and UGC 6526. I have only seen NGC 3813 so perhaps some of those might be in my next list. And then at 10.30 we move on to the final challenge, the NGC 3561 group. Looking at the field with direct vision it looks like a bland field with a few stars. But with averted vision, wobbling the view and effort the galaxies start to appear. NGC 3550 was the easiest to pick out near two stars. It still needed averted vision though to spot. The other three I saw were VERY hard to see. NGC 3552 was just possible. Later I put in my 4.7mm eyepiece which makes the stars less sharp but can pull out slight more in fields like this and sure enough next to NGC 3552 was something else. Turns out it was a mag 15.2 star. I could not see the galaxy next to the star in the image! NGC 3554 was also very tough. It does have a surface brightness of 21.0 which is why I could see it I think even though its blue mag is 15.2! The only other galaxy I could see just with averted vision was NGC 3558. I tried and tried with NGC 3561/ARP 105 but just could not see it. Based on its stats I should be able but maybe the skies were turning against me. I will try again maybe when it is higher in the sky or at a dark site. So although the field contained four galaxies I could only see any one at once so nothing like the photo in my earlier post but still pleasing to pick up four of this group of galaxies about 450 million light years away. Took the telescope down with cold fingers. One of the truss connectors had come away, maybe the cold had caused this, more epoxy glue will fix it... So all in all one of my most successful sessions, still loving the new dob set up. Thanks Callum for the scope still making the most of the mirrors! Clear skies Mark

Just in after a good session. A lovely clear sky but becoming less transparent with time as John has just posted. I will report back tomorrow. Mark

Mike I saw NGC2805 back in January. Very tough low surface brightness object according to my notes. Mark

The chunks should fade, it's the cirrus from the West that troubles me.. Mark

Looking clear so I have been preparing my galaxy target list. I have been doing this for a while so these galaxies are typically mag 13/14 with a relatively high surface brightness in the plough. They have been selected using the skytools software. I have preflagged those galaxies that look possible with my 20 inch dob in mag 5 skies. Normally I have a 90% success rate with this method. I pick those to the N to NE which is darker for me as this is towards the Cotswolds. I have printed off charts to aid with star hoping. I use a RACI finder, then a 16mm eyepiece to locate the field and then a 10mm eyepiece to spot the galaxy. I might get through 7/8 galaxies in a session. So the list: NGC3517/NGC3530/UGC6534/NGC4081/NGC3648/NGC3694 For the finale I will try the NGC3561/ARP105/NGC3554/NGC3552/NGC3550 group to see how many I can pick out. Now I just need the sky to stay clear. If you fancy observing any of these tonight we can compare notes. Mark

I am grateful we have companies like Orion optics still making and resilvering mirrors in the UK. They resilvered my 16 inch and the results were superb. Mark

I also observed Arp224 last night. In the image below I could only see the mag 13.6 star, ngc 3921 and ngc 3916 but I was pleased with that 😀.

I was observing the edge on galaxy NGC 4617 tonight in my big dob. It is a mag 14 object in Canes Venatici. Here is an image. It was hard to spot requiring averted vision. What struck me was that it grew at both ends as I applied averted vision. As I looked at it directly it was clearly an edge on galaxy but as I looked to the side of it with averted vision it grew at both ends. So find an edge on galaxy and see if you can get it to grow and shrink by applying averted vision. It is the galaxy equivalent of blinking a planetary nebula! Mark

Wookie It is steel. Just a basic laptop stand. I was just looking for something suitable and stumbled across it. Mark

They are print outs from the software sky tools. I find I need the detailed maps to locate the fainter objects. It's good that each chart section can be orientated to match my RACI finder / Newtonian view and adjusted to match my frequently used eyepieces.

As I picked up and put down my charts the other night I thought there has to be an easier way. Here it is! Might need lights on the feet to stop me tripping over them.

Wim I saw NGC 2469 when I had a 14 inch scope. I saw it as a small galaxy between two stars. The galaxy required averted vision to spot. NGC 2488 was a lot further back when I had my 10 inch Skywatcher. I noted it as a very tough galaxy to spot with an oval shape. I will go back and re-visit the field with my 20 inch scope sometime. My skies are OK overhead with a limiting magnitude of about 5. Mark

Fascinating image. I have seen NGC 2488 and NGC 2469 visually but you have captured so many more. I must revisit this region. Thanks for sharing. Mark

I have not managed any of these visually. I will make a point of trying a few of the brightest. Which ones have the highest surface brightness? Mark

I have seen NGC 3501 in my 16 inch a while back. It needed averted vision. My note says near NGC 3507 😂 Mark

Just enjoyed reading this fantastic thread. Good to see that Owens galaxy of the month is inspiring people. Here is my list of triangulum visual observations with some overlaps with your images. It needs updating with my more recent 20 inch viewing! Mark

My wife sacrificially ate a quality street strawberry delight sweet to provide the red wrapper for my new astro light.

I always look out for galaxies that I may be able to see beyond the usual lists. This week I spotted Markarian 1199 or UGC 3829. It's part of a group of six galaxies in Gemini above the star Castor. Here is a picture from the web. At mag 13 it looked possible and it was! I used my 20 inch dob Eddie in my semi rural mag 5 skies and it was small but not too hard to pick up. Here is my observation and map. It looks to be about 170 million light years away and a supernova was seen in it a while back. I could not see the companion/background galaxy. I am sure a smaller scope in better skies could pick it out. Try it and let me know if you can see it. Mark

That looks pretty good. Try a star test. Point the scope at the pole star. Use a high power. Now see if you get circles either side of focus and a nice small star when in focus. If you do then your good. Also enjoy the blue pole star companion! Mark

Well my experience with the typical smaller faint galaxies is that higher powers make them visible when they are invisible at low power. I often use a 16mm eyepiece to identify the field but the galaxy is not visible until I put in the 10mm eyepiece. Sometimes I even have to go to a 4.7mm eyepiece. Someone else can probably tell you what that means in terms of exit pupil size. This subject is very complex and there are books devoted to the subject but my opinion is just based on years of observations 🔭 My final piece of advice is try it yourself. Select a few brighter NGC galaxies and try different eyepieces. Is the galaxy easier to see with higher power? Mark