Xilman

Aesthetics apart, the image shows very clearly where the warm dust (predominantly red) and hot young stars (mostly blue) are mainly located within the galaxies.

44 minutes ago, malgpz900 said:

Yeah, that what I'm already using. OK on a hard surface, don't know what it will be like on grass. Probably over thinking a problem I may not have.

 

I've the 250P. On the local freecycle group someone was giving away scrap metal, including four steel sheets each about 100mm square and perhaps 2mm thick. A light sanding down and a coat of paint and, voila, a light-weight easily portable solution to the grass problem.

3 hours ago, Sunshine said:

Something is causing me a headache, it involves the propagation of light through space and time, light from a particular object let’s say an early galaxy 10 billion light years away as spied by Webb. 

...

Is it because as space expands, it’s image as it was five billion year more evolved has not reached us yet? or maybe I’m about to answer my own question by assuming that the universe was a much smaller place when the galaxy was young therefore as space expands its newer light will not reach us as the expansion of space will not allow for its new image to reach us.

Got it in one except that its light has not yet reached us.

You can see this effect on a much smaller scale, inside the solar system even. We see Jupiter as it was about an hour ago because that is how long takes for light to travel from the planet to the Earth. Jupiter is evolving (it has weather, it rotates, satellites are in orbit around it, perhaps casting their shadows on the planet, and so on) and will have changed its appearance "now" compared with how we see it "now". (Simultaneity is a tricky concept in a universe where the speed of light is finite and constant.) Wait for an hour for that new light to reach us and we will see a Jupiter which has evolved by a further hour.

1 hour ago, Craig a said:

That deep feild SMACS 0723 is simply unbelievable, wonder how much it would cost to coat my 10 inch mirror in 24ct gold 😂

 

Not much.  About the same as it would cost you to have the same mirror re-aluminized. Plenty of people will do it for you.

The metal is a vanishingly small part of the cost. The majority is the vacuum chamber and the very precise process control.

5 hours ago, The Admiral said:

IC4617 is a Seyfert 2 galaxy, but I haven't managed to find out what its distance is.

Ian

The redshift is 0.03649 (10) according to SIMBAD. Pop over to https://www.astro.ucla.edu/~wright/CosmoCalc.html and find out that it is around 155 megaparsecs or about 500 million light years.

41 minutes ago, Paul M said:

Ahhh!    look at the end of this post!

Thought about trying for some difficult GCs in our galaxy?  Balbinot 1 is the hardest I have yet managed. I strongly recommend you start with much easier objects first, such as the Palomar GCs.

https://britastro.org/section_information_/deep-sky-section-overview/observing-programmes/globular-clusters/the-gc-marathons-part-i-galactic-globular-clusters

might get you started.

One day, if and when some round tuits become available, I will issue a first cut at the second article in the series.

4 minutes ago, Paul M said:

I always like to see other people's images so fire away!

Happy to do so, but in this thread?  It is just about on-topic, IMAO, given that it started with an image of a GC.

Here is an image of 50-ish globular clusters. See https://britastro.org/observations/observation.php?id=20190311_020000_9a2c47fcf9f3ee97 for details of the observation. Different processing of the same data revealed another dozen or so, which is also available in my BAA gallery

17 minutes ago, Paul M said:

Ahhh!    look at the end of this post!

Just a thought: have you located stars of very similar brightness to the GC in your image and compared their appearance with Mayall II? Aladin-Lite will likely let you do that.

If other stars of that magnitude are noticeably smaller then you have shown that the GC is non-stellar.

IIRC, it is about 3 arcsec across. Within the seeing disk for most imagers but readily non-stellar for visual observers with their 100ms integration time.

Nice!

Thought about trying for other GCs in the Local Group, or even further afield?

I can point you at some of my images if you wish.

On 07/07/2022 at 21:09, Paul M said:

And very deserving it is too! I think Globs are, overall, my favorite DSO's. Mesmerising to look at, and mind boggling to think about.

Lots of pretty GCs to image.

I urge you to image difficult ones. Much more a sense of achievement, in my view. Try starting with a Mayall 2.  It's quite bright, easy to find and big enough not to appear stellar as long as you use a high enough magnification. It is M31's equivalent of our ω Centauri. Should be visible to someone looking through a 20cm scope and a decent but unexceptional sky, and easily within the range of a 60mm refractor and camera.

After that, pick up hundreds of GCs in M31 and M33; dozens in M81 and who knows how many in the Virgo cluster. M87 alone has over 12 thousand GCs known, hundreds of which are accessible to amateur imagers.

14 hours ago, Ags said:

Your argument is based on Euclidean geometry which Flat Earthers have long since disproved.

My argument is incorrect even with Euclidean geometry and the rotation axis (whether of sky or Earth) perpendicular to the plane of the Earth.

Hint: what part of the sky is seen by an observer standing at the edge of the Earth?

45 minutes ago, Ags said:

It is riduculous to think the Flat Earth rotates. It's the sky that rotates around the flat Earth.

Makes no difference.

If the axis about which the sky rotates is perpendicular to the Earth only half the sky is visible (neglecting refraction). The other half rotates below the Earth where we can not see it.

(Yes, I am well aware this argument is incorrect. I have known my reasoning to have been incorrect all along. I will explain in detail if no-one works out why and posts the correct analysis.)

53 minutes ago, newbie alert said:

It is, don't let those globe freaks fool you🤪

We live on a flat earth, within a container...the edge is guarded by NASA, you can't cross it to go on the flip side...  Who would think we live on a spherical globe.. the water would fall off... Obviously...🙄🤪😱🤔

The container being the circumfence, presumably? They work for Ringworlds and Banks Orbitals too.

Personally I think we live on a pseudosphere which has global constant negative curvature (with tiny local variations, of course, like mountains). That is why it is so hard to reach the north and south poles and no-one knows exactly where they are. Travelling around the pole is easy but travelling to them ...

On 09/07/2022 at 06:57, MarsG76 said:

HAHA. depends on which theory you're quoting...

Fair enough, I was thinking about the Discworld where the rotation axis is perpendicular to the disc and my claim holds.

If the rotation axis lies in the plane of the disc then one could indeed see the whole sky.

3 hours ago, MarsG76 said:

Unfortunately we can't have it all... there are so many northern objects I'd love to see and image... if only the earth was really flat, we'd have the best of both skies...

Nope, quite the reverse. If the Earth was flat, almost half the sky would be invisible without space travel. Think about the geometry. With a spherical earth everywhere can see more than half the sky. Even at the poles atmospheric refraction will give you half a degree the other side of the celestial equator.

So, I have M31 and M33, where I image globular clusters and measure variable stars like AE And and AF And. You guys have the LMC and SMC which are much easier to study.

I'm jealous.

NGC 6752 technically rises from Tacande observatory because anything with a declination north of 62° S is theoretically visible and NGC 6752 is at 60° S.

However, the ridge to the south (and now the new volcano cones) blocks the bottom 10 degrees or so and the telescope mounting sets a limit of 47.5° S.

Perhaps a trip up to El Roque with a pair of binoculars is called for. Pretty sure I can't do imaging from up there and an object which culminates at 2° is not going to be very impressive.

On 03/07/2022 at 17:07, Shelley withers said:

Hi ,I'm Shelley 

I'm new gre  I'm trying to find a telescope I was left ,

It's a H. N .Irving here's the picture  if Anyone  can Help me identify thus telescope   I'd be  very grateful.

 

Is there anything on it which might suggest a date?

I'm starting to renovate an Ottway refractor made in 1912 and would like to find out some more about it, but that's a matter for another thread

14 minutes ago, Whirlwind said:

I'm working on the principle and looking at the website that they are doing follow up detections.  Many of the space telescopes and even ground ones focus on cooler red stars.  Not only are the stars smaller, so transits have a larger impact they also occur more frequently.  On top of this their habitable zone is a lot closer to the star (so it's easier to identify potentially habitable planets).  Hence there is sense on what they are telling you as I expect many of the follow up stars are M and K stars.  Once you start to get hotter stars then a lot more flux is outside, what I assume is the R band filter.  Hence there is a balance that yes, red filters do reduce your noise but then you are also filtering a large fraction of light in bright, hotter stars.  However from a guidance perspective one simple message for the public is easier to explain.  It also ensures greater consistency of data (is the depth change because of noise or because it is a binary etc).

Yes, binning in time is for higher SNR, for most observatories (barring very large telescopes) you generally run multiple observations of the same object over and over to get the precision as you can phase fold the data.  But again the consortium are doing that with the various data sets I assume (again preference for consistency would be key in this approach).  On the other hand if you are doing it for 'fun' and just want to evidence you captured the object then time binning is likely to show the transit easier. 

Phase folding: the primary objective of the Exoclock project is to get accurate mid-eclipse timings. Mostly so that they can be predicted years in advance when the satellites fly. Time on them is limited and you don't want to miss a transit because the predictions are 20 minutes out based on ten year old observations! As I noted, the interest from amateur observations is accurate timings. Precise light curves, spectroscopy, etc can be done later by professionals with kit which does not yet exist.

Just now, Whirlwind said:

For exoplanets you really want as much signal as you can get.  I think this might come from the principle that many short period planets are around cooler stars as even at short periods they might be habitable.  However around brighter hotter stars a red filter is just cutting out flux more than any benefit you will get from seeing or sky noise issues.   There is some benefit from using filters to identify binary stars (as depths will change dependent on the filter band).  But really you want as much signal as you can get.  If it is noisy just bin your data in time (not on the camera).

I was only passing on the advice given by the Exoclock collaboration.

As I understand it, which may be imperfectly, the use of a R filter can reduce the noise (from sky and from seeing) by more than the signal compared with unfiltered.

As for binning, I generally use 2x2 binning on the images downloaded from the camera. It doesn't reduce dynamic range but it does even out pixel-to-pixel sensitivity variations and it does reduce noise.  My advice: bin in time only if absolutely necessary to get the SNR. With a transit what is much more important, in pracfice, is precisionin  the orbital elements rather than in the size ratio of planet to the star. The former requires precise timing, the latter precise magnitudes.

But what do I know? I am not an exoplanetary expert, I just work with them.

10 hours ago, AMcD said:

Have now managed to get it working @Xilman.  Moving from Anaconda to a simple Python 3.x installation with pip installs of the required packages worked.  Many thanks for your help with this. 😃

That's good, and basically how I did it though, as I said, python 3.x was already in place.

5 minutes ago, AMcD said:

That is a very good point.  The short answer is I do not know.  I find AstroImageJ a very complex programme to use.  I am quite new to this aspect of the hobby and at the moment am at the 'follow what it says on YouTube' stage 😀

My lack of software prowess is probably demonstrated by the fact I have spent most of the day trying to install HOPS, as kindly suggested by @Xilman, via repeated reinstallations of Anaconda without success.

Yes, it can be a bit of a [removed word] (a technical term from the IT industry). It helps enormously if Python 3.x is already installed and you don't have to mess around with Anaconda.

I might be able to help out, and the authors are very responsive too.

4 hours ago, sorrimen said:

That's great advice all, I'm actually yet to look for any clusters yet so this should be a nice little challenge and something to look forward to. I've snapped a couple pics of andromeda and M51 (only confirming it was M51 about two days later as it was my first DSO) and as you say there is some blurring, though from a bortle 7/8 it could be worse. 

Also would be thrilled if you tried it out too Xilman! I coincidentally go to university in Cambridge so I imagine we'll be observing from a similar area some of the time.

 

We should meet up for a beer (or intoxicant of your choice) some time. I'm near Cambridge for 2-3 weeks, then off to La Palma for perhaps a month.

Drop me a line.

I have been recommend to use a R filter to reduce sky brightness and seeing. If you can't get a high enough SNR and cadence filtered, use unfiltered.

Have you tried using HOPS? https://www.exoworldsspies.com/en/software/

It has very good reviews and is recommended by the BAA-ARPS exoplanets sub-division.

I downloaded it a few days ago to see how well it worked against my home-brew software but haven't yet tried it out.

21 minutes ago, happy-kat said:

For some ideas you might like to see what's in this section

https://stargazerslounge.com/forum/283-imaging-challenge-24-android-vs-ios-now-closed/

Field rotation can be cropped away but if exposure isn't short enough the central target can become smeared.

Brighter DSO would be more suitable targets, globular clusters might be fun to try.

Ross:

Note that it is often possible to restore distorted images with software.  Just because it is possible doesn't mean that it is necessarily simple.

In my experience, stacking is almost always best done by first plate solving each sub and then stacking on the WCS (world coordinate system) placed in the header of each sub by the plate-solver. The only exception (again IME) is when there are too few stars for the plate solver to succeed.

I second clusters. Open clusters might be even easier because their stars are generally resolved right the way through.

Good luck, and please report back on what you achieve!

(Added in edit: Actually, I have similar kit here but have never tried DSO imaging with it. Perhaps I should and we could compare notes.)