Mike JW

Neptune was close to  a mag 10 star last night so I observed it visually with the C11 and then popped the camera into the focuser.  11 x 1 sec subs. Triton showed up nicely.

Mike

On the same evening as sketching Atlas and Hercules, I wandered over to Crater Burg. I was fascinated by the multi shades of grey , something I do not recall seeing so a sketch was in order.  Burg is 15 to 20 km across and is known as a complex crater despite its relative small size. It has a central peak ( are there two tops - I thought so at times but could not be sure. Professional images do indeed show twin central peaks).  The small crater floor  was a definite darker shade with very obvious terrace walls giving rise to the different shades. What is also interesting is that the crater rim looked a bit irregular at times.

This is the second time I have sketched this crater. Last visit I saw more of the wrinkle ridges that lie around it but less detail within the crater. (Different illumination). Last nights sketch is on the left.

Mike

Thanks everyone for your kind comments. Mike

Another clear spell saw me out there looking along the terminator just before midnight, when I stumbled across Atlas and Hercules. The shadows from Atlas indicate a very jagged crater wall made up of several major peaks. The floor of Atlas is very rough indeed. Atlas would appear to have steep terraced walls. Hercules has a  much gentler appearance and has big crater within its floor. Both these craters seem sit on a raised plateau of very rough terrain - need a decent all terrain quad bike to scoot around this area as well as some serious climbing kit to reach the sharp peaks.

To the right of Atlas is a much eroded elongated crater, presumably much older than Atlas and Hercules as well.

Two craters near the terminator have very long shadows - I assume this means they have high walls and judging by how black the crater floors are this would seem to confirm this idea?

The mountain tops in the blackness of the night gradually got dimmer over the 1.5 hours I watched this area as the sun gradually dipped below the lunar horizon......

Mike

Great description Mark. Mare Crisium fascinates me as it changes under different illumination.

45 minutes ago, Lurcher said:

Hahhha!! Why change Mike!!??

Don't what to get stuck in a rut!! 

"I did a sketch of the Cleomedes, Burckardt and Geminus craters" -  I thought about those. Burckardt is just on the edge of my sketch.

Actually I was tempted to not draw at all because it was fascinating to watch mountain tops disappear into the black, shadows lengthen, cliffs becoming highlighted....

Mike 

It is not often I look at the waning moon but last night it worked out. Mare Crisium was stunning. So much detail and the wrinkle ridges very much in evidence.

I enjoy seeing the technique used by Martin (Lurcher) so I gave it a go but the result is so appalling I am not prepared to post it. The technique is so different to my normal approach that I could not master it. I think I try to do too much detail. So hats off to Martin.

Below is my normal technique but not as good as I would like it.

Mike

On 12/10/2019 at 16:22, Lurcher said:

This is a great thread to read through. I would love either the 450mm or of course, why not,  the 500mm version!

I remember reading a report on this scope in The Sky At Night Magazine and they said something along the lines of "this would be a great scope if you were a club that wanted to invest in one", which made me think I was being ridiculous for thinking it was the next scope for me one day, so it's great to read that individuals like yourself and "OldFruit" have got one and they're not just for clubs to own.

Got to love large dobs.

I look forward to hearing more. Oh I was going to ask, can you have a look and see if you can make out the central star in the ring nebula the next time you're out with your scope please? (Just been wondering that on the thread about a 350mm flextube). I've never been able to see it.

Cheers!

Hi Martin,

I use to own a 500mm Dob and using under Bortle 5 skies I saw the central star just twice in M57. In a 24 " it is somewhat easier. Under dark skies than the 20 would have picked it up much more regularly.  Mike (as in lunar sketching threads).

PS a 500mm scope will noticeably out perform a 450mm scope but will be harder to transport. My mates 600mm blows away the 500mm but is a beast to transport.

Hi Martin and Mark,

Doubles fascinate me. I have made doubles data bases (excel) for all the northern constellations , based on the 2nd edition of the Cambridge Double Star Atlas. These doubles in this 2nd edition are true doubles (or multiples), rather than optical ones. Most have SAO numbers.

I have attached an example which has my notes in it as well. I could supply all my lists - very happy to do this. Is the forum the  correct way to do this?

Andromeda doubles Cambridge.xlsx

Sissy Haas book is very good.

As to the best way to present a doubles sketch - there are as usual several approaches. Sometimes I will include details, other times I go for the art effect........

Mike

Impressed. Never heard of the WBL galaxy groupings. Mike

Hi Martin,

You have set me thinking with this image as to what I might be able to locate. I have never really investigated the Abell Clusters - not enough time........ Mike

Hi Rob, I have just read through your method of sketching - great idea - beyond my knowledge. I like the final effect. I think I would agree with you that the background could be a tad darker but as you say it is not black (except at high magnification). I have often visited these doubles so thanks for reminding me of them. Maybe I should get back into sketching doubles. I always find folks descriptions of the colours interesting. Folk see them differently to each other. Mike

Thanks for posting. Brings back memories of my visits to M74. Beautifully and accurately sketched. Mike

Hi Lurcher, I had been missing your sketches so thanks for posting. I have enjoyed your sketch and technique. Amazingly so I have never sketched Copernicus. Cheers, Mike

A lovely area to explore and good to have your input back into the section. Mike

8 hours ago, RobertI said:

I’ve added a screen shot from the deep sky survey as a comparison - hope you don’t mind! You’ve definitely got a dark neb and I think your lower exposure has picked up the knots in the northern arm which are not visible in the ‘over exposed’ DSS image. 

 

Thank you - good to to have a comparison. Mike

Ruud - exhausted!!!! reading through the technicality of your technique - totally in awe. Keep posting. Many thanks. Mike

Hi Gyuri,

An excellent attempt - well done. My skies are just good enough to even attempt such a difficult target. Mike

Beautiful work. I like that fact that you have done the sketch when the moon is waning - lunar sketching at midnight it not something I have ever done - too tired!!!

Mike

Galaxy hunting in Aquila is not the place to go but 6926 is well worth a visit. It is classed as peculiar spiral - I would call it well and truly messed up, but what caused the distortion? There are no obvious candidates near by (6929 but that is not distorted). In its distorted northern arm (up in my shot), there are two distinct star knots.  The west side of the galaxy has a definite slightly curving dark lane.  To the south of the core there appears to be a dark area (dust?)  Off to the east is 6929.

Mike

NGC 750 and 751 are an interacting pair in the constellation of Triangulum. They are both elliptical and together form Arp 166. They are about 225 million light years away. I picked up just a hint of the tidal stream and pleased to pick up the bright bridge of stars that link the two galaxies. I have circled other galaxies.

Mike

If I use my ultrastar , 0.5 reducer with my C11 then vignetting is obvious, Thus I assume at this F ratio of F5 then the chip is not fully illuminated. If I use the f6.3 reducer there is no vignetting. 

My question - is there a general formula to work out F ratio to chip size such that there is no vignetting (or minimal).

I would like to try different cameras but do not wish to buy one that has the wrong chip size.

Thanks, Mike

24 minutes ago, JackCooke said:

I don't think you're as far off as you think! If I get to your level I'll be mighty pleased.

Thanks for the encouragement. Maybe on a dark wet winter day I will do another dotty sketch. As Lurcher  indicates, Erika Rix produces excellent work - much to learn from her drawing skills. Mike

Last time I tried Sharpcap it floored me but at least this time I made more progress. Thanks for the link. Mike

Hi Steve,

Again, very impressed by your achievements. Since the last posting I have looked at your link, downloaded Sharp Cap, read up as much as I can and then had two sessions using my set up and Sharp cap. I found it totally frustrating - very confused by Sharp cap as to what to do. The results were just rubbish, confusing as to how to save a shot, confusing as to how to use the histogram, confused by live stacking and getting it to align......... Normally I use Ultrastar camera and starlight live - it is so intuitive, so easy and I do not have to understand anything to get a reasonable shot. So today I uninstalled Sharp cap and decided to stick with the Ultrastar. Need someone to sit with me to understand what to do..........Unfortunately until I can get confident with Sharp cap it rules out all cameras other than the Lodestar/Ultrastar which is not where I wish to be......

Mike