Fraunhoffer

Ive not tried an 80a. 

I do like the way you have been able to capture the bright sunlit parts.

2 hours ago, josefk said:

What a productive night @Fraunhoffer super and super sketches. Ptolemaeus caught my eye last night. Cold wasn't it!

Thank you. It was cold. It was nice for it to be so cold that it was dry though.
I have a an old fur lined 'fishing suit' from a neighbour and some 'charcoal' foot warmers, so I stayed reasonably warm.

I felt like I was floating in space this evening. Nights like this do not come along often, and even though it was cold, and the forecast was expected to drop to -4 C, it was not to be missed. The cold air from the last few days had made the sky very clear so not only were the celestial sights sharp, but the light reflected from the surrounding light pollution was minimal.

The early evening had some very enjoyable views of Jupiter with variations in the belts clearly visible. I was able to reach 250x magnification without the picture turning into a fuzzy blob, thanks to the clear and stable air. No red spot was expected this evening. A tour of the terminator along the half moon provided some wonderful detail of craters, valleys, mountains with long shadows, strange undulating plains and rills. It really felt like I was in orbit and travelling above the surface.

Uranus was not far away and so I thought I would look at this faintly coloured ball. Surprisingly it was accompanied by three very faint dots this evening. After some research, I was delighted to find out these were three of its moons. This is the first time I have seen this. Uranus has a strange inclination so I think the combination of the clear sky and the particular orientation at the current time enabled this.

Orion was reaching prominence due South a bit later and the customary examination of the huge M42 nebula was required. The centre trapezium was very clear, although I couldn’t make out the additional 2 faint stars to make the 6. One day!.  The nebula did not disappoint and under a high magnification the wings spread across my whole field of view.

After an interlude to warm up with some hot soup and catch a bit of sleep, the streetlights turned off at 1am (hooray) and the sky became noticeably darker. Leo was now in the south and so I looked for faint galaxies in this region of sky. ‘Galaxy season’ is almost upon us where we can look out of the milky way into deep space. Despite the extinguished streetlights, the sky was still a bit grey which frustrated my search. However, I did manage to catch several Messier galaxies: M95, M96, M102 and its companion NGC 3384, M65, M66. The nearby NGC 3628 the hamburger galaxy was just too faint to see today.

Comet ‘62P/Tsuchinshan’ was in the vicinity and after struggling with various apps to try and find out exactly where it was supposed to be (it helps to know exactly where it is when looking for faint things) it came into sight as a bright dot surrounded by a faint fuzzy patch. On another night I might try the camera to record a bit more light.

I was by this time starting to feel quite cold and tired, so I finished the evening with some lovely bright star clusters M53 and M3. It only seems a short time ago that I was seeing M3 as an evening object, and here it was coming around in the morning. Where does time go?

Super.

I really am going to have to try black paper.

Do you use a selection of pastels, or mainly one? Im assuming the stars are with a pen? 

On 25/07/2023 at 13:27, Mr Spock said:

Here's my two ready for action. The Dob is next to the shed, and the Tak can go anywhere. Especially useful as my house blocks the East so I can only see there from the top of the garden. The garden runs exactly East to West - North to the right and South to the left 

Now why didn't i think if putting both up in different ends of the garden. 🥴😆. Btw whats your dob sitting on.

A quick sketch from last evening.
A clear-ish sky. It looked pretty milky to me so it was Jupiter and a few clusters. The wind was very blustery, however I did get a nice view of Jupiter in the moments the 'scope wasn't being blown about with a bit of detail in the bands.
I thought I would try a slightly different technique this time. Shading in some black sky and then trying to remove that with an eraser pencil and shield to reveal the brighter areas and then re-touch the detail.
I'm not sure it worked. I need some more practice.

Another fan of a chair.

Also I find the better views are late into the night when the air has cooled down to its overnight temperature and become more stable  and the dew has taken some of the moisture out if the air. I think someone already commented before dawn a good time.

I took up sketching a while back, not because im any good, and i found it helped me slow down and be really patient to see things.

+1 "Left turn at Orion"

Best guide to the night sky i ever bought. 

Nice cover shed.

Just a thought about sealing or protecting the wooden base in some way if it's made of chipboard particle board. Good comments about airflow and humidity drier etc.

I bought a used SW one  a while ago and the base had got damp at some point in the past and swelled. 

Thanks. Forgot to put that in the op.

Celestron c8, with cc (i tend to leave that on rather than keep swapping it on and off), 2x barlow, 10mm uff. Neodymium filter. 

When i put the filter on the barlow or the eyepiece i seemed to get some internal reflections. The reflections were much reduced by putting it on the scope end of the diagonal.

I just liked the S shaped shadow and the valley when i saw this. Since i had my sketchbook out anyway..... It did take me some time to locate it on the map later🤣

Between mare tranquillitatis and mare nectaris.

My local seeing wasnt that great with air wobbling over the  rooftops with everyone's heating on, but i was delighted to get my sketchpad out and get in the zone. 

I tried a neodymium filter in the end of the diagonal which helped a bit.

On 08/11/2023 at 17:59, vlaiv said:

I was going to try and use an old photo exposure meter, but i dont think it goes low enough. I can read to 1.4 lux and with a bit of faffing about with the settings, maybe 0.35 lux.

Plan B is to cross check my mirror less camera with the exposure meter and point the camera with a 30 deg fov straight up at my grey sky and adjust the camera exposure until the 'average' setting says +-0. This should put a sharp histogram peak in the middle. Then work out extrapolating the setting to get another estimate of background lux. in c/m^2

I thought one of the table values from my exp meter might be useful.

Asa 50, f/2.8 , 30s is listed as 1.4 lux., so im thinking by cranking up the camera iso i can get an estimate of sky background. At, least to compare sites.

20 minutes ago, Albir phil said:

I suppose it would give you a measurement of sorts, but in the end sky quality is something we have to accept, are you thinking more like build up your own sky quality maps using the exposure meter. I think it would give you a idea on the night which you could then compare with other nights in the same location.,it is something I thought about at one time but never tried it Good luck 🤞👍

I agree. Not much I can do about it. It would be useful to have something a bit more objective as I search for 'better' places to observe from.
Something more than stepping out of the car and going mmmm 🙂 

Having browsed the various 'sky quality' maps I wondered if it was possible to get a more accurate estimate of local conditions using a photo exposure meter.
I live very near some huge light domes, on a corner with 3 street lights and in a slight dip below a hill that seems to attract mist when the temperature drops.

I wondered if this sort of measurement was possible (I have an old exposure meter to hand).

Thanks

12 minutes ago, Graham Darke said:

Nice! Tracking platform?

Just the normal Skywatcher Truss-tube go-to tracking.
I replaced the bottom two wooden disks on mine with some well made marine play ones that were dead flat (to within 0.125mm) so the alignment, go-to and tracking are now spot on. (Or, as good as I can make them anyway)
I might have been able to do longer exposures if the target was in the west (where the ecliptic plane is almost straight). 15s is the most I could do without eggy stars on this occasion.

I took my Dob in hand in the end (300p Skyline) and made a new base for it.
Wearing my 'engineers hat' it seems the lower wood disk (original Chipboard) swells up after a time. In my case 2mm!. The result is the telescope tilts as it rotates (think fairground Wurlitzer ride).
Its only a bit, maybe 0.5 degree, but that's the width of the moon and the result is the alignment reference plane is then tilted and the stars are off using the go-to.
I chose some good quality marine play and finished it to be plat to within 0.125mm.
Result - my goto are within half the fov of a 10mm eyepiece. That's about 5 arc minutes, which is the stated spec of the Auxiliary decoder on the base unit.
Well pleased.
Conclusion - look after those wooden baseplate disks.

Ill get around to do the rest of the base in looovely wood next Summer I expect.

M33 has been on my hunt list for a very long time and I was pleased to see it and capture a picture last Saturday. 14 Oct 2023.
Surrey, England.

72 x 15 s exposures, (18 minutes total). Sony a5000, Skyliner 300p Dob', Coma Corrector, DSS, Affinity Photo and Topaz Denoise.

Slightly odd question that is a hangover from my previous hi-fi days. It was said that spikes helped control vibration. Eg speakers and turntables had spikey feet. (Did wonders for the furniture). I note that some high end gear still has spikes.

So, should tripod feet be spikes or rubber blobs do you think ?

Hi all,
After much fettling with my rather aging 'chipboard' mount, I noticed last night that the two large flat round boards making up the turntable base are slightly dished.
This probably affects the rather iffy goto accuracy as 'level' means different thing in different places.
I was wondering about making some nice marine ply replacements for the next project and I wondered if anyone had a pattern for it.
I have the 12" Mk1 version. Its not a very complicated shape and I can make my own no problem after taking it all to bits and measuring up.
However, I would prefer to have the new wood ready just to swap over and prepping it all might make a nice little slow winter project when its not starry.
Anyone ?

Cheers.

 

A quick sketch or Mare Crisium 2023-09-02.

On 31/07/2012 at 12:07, squeaky said:

All that stuff in the centre contains the friction clutch for the azimuth rotation

There are two grub screws in that locking nut, so release them a couple or three turns

Then use a 25mm spanner to undo the nut

Below this are two cupped spring washers - lift them both clear

Now lift the gear and clutch plate assembly. You may need to slip the spanner under it to gently ease it up

You can now see one of the two clutch plates in the centre

The other is underneath the silvery disk sitting in the centre of the gear wheel

They should be dry, clean, free of grease and have no discernible rough areas or score marks.

Be very careful handling them because you are pretty much guaranteed to have grease on your hands by now.

If you need to strip further to clean up between those main circular disks and the black "plastic" thing then the four screws in the centre here have stiff nuts (on a cover disk) underneath the base.

From here on in - reassembly is the reverse of this disassembly so you just need to follow the pictures back up.

When I tightened up the locking nut above the two cupped spring washers I did it finger tight and then gave it an extra quarter of a turn with the spanner. It's quite difficult trying to asses the right amount needed here. It felt easier than it was before stripping - but now that it's ALL back together I think I could possibly have got away with adding less pressure when using the spanner. I'm going to leave it as is though until I do some imaging tests.

So that's the basics done if your tracking is really bad and jumpy like mine was, or if your dob feels as though it's stiffer to move around by hand than it used to be.

After image testing, and possibly a quick tweak of that spring cup tension, I shall be heading for the accuracy thread to get some fine tuning done. At least now I'm familiar with all the bits and what they do

? How is the decoder shaft attached to the bottom clutch plate (last pic) please. ?

I think the holes in the bottom clutch plate on mine have worn as the plate moves slightly when the top is rotated ( so the decoder doesnt detect a movement).

3 minutes ago, Spaced Out said:

So I got this today, £30 off ebay. It goes up to 10ft tall, a bit higher than our garden fence and blocks the offending streetlights (you can just see them on the right side of the pic). Seems ok just need some sandbags or something to add weight to the feet and stop it blowing over !

Great. another possibility is some carefully placed guy ropes - as long as you dont trip or strangle yourself in the dark.

I have 4 extending  washing line poles in a square that slot into bits of old pipe in the ground with cable washing line between them. Then i hang black sheets from the cables. 

I hide in the middle with my scope.