Astronomist

The earth's atmosphere is quite opaque to both x rays and most microwave wavelengths, and thus these signals are observed by space telescopes. I assume whoever made the graph just didn't have any space telescope data available.

20 hours ago, TiffsAndAstro said:

are you taking flats at all?

No, I am not. I dont see there's much point, I haven't encountered much trouble with gradients because most of the frame ends up getting cropped out of the stack due to my nudge-drift-nudge tracking.

24 minutes ago, Norris Adams said:

I'm intrigued how you managed to acquire these image without tracking?

This is achieved through a steady hand and careful nudging, with the camera set up so that the object drifts straight accross the frame. The downside of this technique is that one does not have as much time to view the image. I am limited by my own patience to about 1000 x 400ms frames. 

Another option that might be worth a look is the new ASI676MC - it has 2μm pixels but offers a bigger sensor area than the 678, which may be useful for lunar. it is quite a bit more expensive though, and I suppose there is always a small risk associated with buying a product that is new on the market.

On 19/05/2024 at 22:54, Richard_ said:

With the release of the IMX585, should I negate the other cameras on the list?

No! At the current level of technology there isn't a lot to choose between the newer cameras; something else will almost always be the limiting factor (I have no idea if this is true in DSO imaging as well). Best to go with whichever is the best match to your scope / use case in terms of pixel and sensor size.

Just now, woldsman said:

Can radio signals be lensed

yes, they can.

9 minutes ago, TiffsAndAstro said:

Sounds awfully risky putting more  transmitters/relays in space.

We have been beaming radio waves across space for nearly a century, I think if anyone was interested in us we would have found out about it by now.

Here's Petavius, and the surounding area. Captured last night in twilight, all around 30% of 800 frames, captured with sharpcap, stacked in autostakkert 3, and post processed in astrosurface. The first shot was converted to monochrome in post processing. 

Altair Hypercam 585c, Bresser 10" dob (manual), and Stellalyra 2x 2" barlow.  On reflection I think perhaps my focus may not have been quite right.

That is puzzling @Vroobel, only thing I can think of is maybe the camera sensor tilt is not quite right?

3 hours ago, He-Man said:

Prices just got a huge bump again.

I hadn't noticed - perhaps the prices are different over the pond?

17 hours ago, Martin Meredith said:

I'm interested in your prime focus arrangement. Do you mean that you are foregoing the secondary altogether?

No, I am using the camera in the normal focuser on the side of the tube, with no reducer or barlow. I'd definitely give it a go with your 10"; you should be able to do much better than me since you have tracking. I'm not sure how accurate StarSense is but I'm guessing it would help with getting the target on the sensor, which I have found to be tricky with the dob. 

I had intended to have a go at the Owl Nebula this session, however rather embarassingly after half an hour's searching I was unable to find it in the eyepiece.🤣 

Instead I tried to improve on my previous attempt at M82. This is 800 x 400ms exposures, at 60% gain.

And here's a bonus pic of procyon and its spectacular diffraction spikes:

Thanks for your advice everyone, Last night I had another session on M81, with dramatically better results. Gain was half the camera's maximum. 

1272 x 380ms exposures: still noisy but better than my previous attempt by a long shot. 

59 minutes ago, PeterC65 said:

I'd suggest lowering the gain and increasing the exposure time.

I can't really increase the exposure time much as the scope has no tracking, but I might be able to get up to 400ms without too much star trailing. This should allow me to lower the gain quite a bit. I will attempt to give M81 another go tonight, but with longer exposures and more of them. I also see Sharpcap has the option to use darks; is that likely to make much difference?

Here are the fruits of my first session with my new Altair Hypercam 585c. In the absence of anything brighter and more spectacular I went for M81 and 82 (separately, my FOV is too small to get them both at the same time). Both are ~300 x 300ms exposures at prime focus on my 10" dob, at the camera's maximum gain of 136500. Capture and stacking done in Sharpcap. Annoyingly, the use of a high gain has made the results very noisy, but this is still way better than the eyepiece view from my Bortle 6 location.

While there is lots of room for improvement, I'm quite happy with this for a first go! 

On 20/04/2024 at 10:44, wesdon1 said:

Is it the cooled version or just fan cooled?

It's the fan cooled version, I don't really need the full tec cooler as I don't plan to use it for long exposure imaging. It seems to be a very well made item, fit and finish is better than the ZWO asi120 I had a while back. 

Best of luck with your potential purchase!

DPD left this on my doorstep today- about 3 weeks late because they lost the first parcel. Also Altair Astro's communications are quite slow, as I'm sure many of you have already experienced. Anyhow it's here at last, and the sky is looking clear-ish. I've just tested it against the neighbors chimney pots, the sensitivity compared to my DSLR is amazing!

3 hours ago, wesdon1 said:

what is that name of the manufacturer that is illegible in the photo?

On 16/04/2024 at 12:12, jp1977 said:

this particular telescope (which is a Seben Big Boss 150/1400 6" bird-jones style)

Here is the finished article, after 3 coats of Everbuild clear satin varnish. The varnish has darkened the wood a little, which I am quite pleased about, and hopefully should keep the mount safe from the elements for years to come.

I also made a matching Telrad finder shoe adapter thing with some offcuts, as my old one (visible in the picture in the first post of this topic) was a bit loose fitting and didn't always stay put.

clear skies!

You should be able to spot the pup in either of those scopes, the major obstacle there is seeing. I finally spotted the pup for the first time this year in my 10", after about 20 unsucessful attemps. In theory it should be quite easy at that aperture, but the seeing in my area is usually awful...

Best of luck with your future scopes!

Thanks for your kind words everyone, I was able to test the new mount last night (thankfully the grass was dry) and I can confirm it works very well, dampening time after a nudge is pretty much halved from the original version, and the square cut outs make it much easier to lift the scope in one piece when dodging trees. Unfortunately there is a little excess stiction on the AZ bearing, which I will attempt to sort out today.

12 hours ago, Alan White said:

Wood Butchery is my level.

Likewise...  look closely at the pictures if you don't believe me. An electric sander and some filler can cover up almost anything.🤣

Hi everyone

Here's some pics of the new rockerbox I've been building for my 10" Dob. The original particle board base has served me well for a while now, however it is starting to fall apart and go rotten. I managed to get hold of two sheets of 1" beech faced ply for free recently, as I figured it would make a good rockerbox for my scope.

The design is heavily influenced by @Moonshane's build, linked here: Home made Dobsonian Base. - DIY Astronomer - Stargazers Lounge

The new base is very stiff, as well as being significantly lighter than the original. I have reused the azimuth bearing ring and pads from the old base, in addition to the aluminim bushing thingys around the centre bolt. The eyepiece tray has also been retained, albeit in a more convenient position. 

All I need to do now is stuff up the gaps left by my shoddy carpentry skills with filler, and give it a few coats of varnish, or else it may end up just like the old one quite shortly. 😨

clear skies!

Welcome to SGL from salisbury, on the other side of wiltshire! I'm sure the folks on here will be delighted to help you spend your money.

43 minutes ago, Earl said:

with greater bandwidth surly the same proces can be done with digital optical images

I assume this would have been done already if it was possible. Perhaps the computing power required is unfeasibly large?

You are referring to optical interferometry. As far as I am aware for this technique to work the light paths of the component telescopes must be physically brought together, meaning it simply is not feasible over the very long distances you describe. AFAIK the largest optical interferometer is the VLT at ~140 metres maximum baseline length. For radio telescopes however the data can be brought together via a computer, meaning extremely long baselines of thousands of miles are possible.

17 hours ago, PeterC65 said:

Have you tried using SharpCap?

I didn't realise SharpCap could be used with a DSLR - apparently it can but needs an ASCOM driver. I would try this, but I should have an Altair Hypercam 585c arriving in the next couple of weeks so there's no point wrestling with drivers for the DSLR.

1 hour ago, Martin Meredith said:

I'm just wondering if your debayer settings were correct, as that might explain the green-blue cast?

The debayering is all done automatically, so probably is all wrong, and as far as I can tell you can't adjust the colour balance of the live stack manually.