New Feature : Deep Sky Image Annotation

[admin]

Hi,

there's a lot to be said for that approach - you will always get better stacking results if you use a dedicated processing application, or better planetarium results with something like Cartes-du-ciel, and so on. However, running multiple applications is not always the easiest way to do something, so my approach has been to try to do a little of each of these tasks to make astrophotography easier. It's for this sort of reason that I don't want to add catalogs by default that contain hundreds of thousands of stars or galaxies - instead I make it possible to add those for people who want them.

What I am looking for is catalogs of popular targets that might be useful to a decent fraction of SharpCap users - maybe a catalog of a thousand planetary nebulae or something...

cheers,

Robin

[Tfer]

Robin, is it possible to give a few color options in the annotation?

I regularly use the inverted view, and the yellow print washes out against the white background. The ability to change the font color to a deep red would be especially handy.

[admin]

Hi,

rather than another option, what about if the colour tied into the inverted setting automatically (ie used darker colours when inverted was switched on)?

cheers,

Robin

[Tfer]

That would be perfect.

Thanks Robin.

[marekc]

I have a feature request for Deep Sky Image Annotation:

I think it would be great if the annotations included the redshifts of the galaxies and quasars.

In other words, all of the external galaxies and quasars which are shown on the annotation overlay would have their redshifts listed, along with (or, optionally, instead of) other parameters like magnitude or RA/Dec.

I have really enjoyed doing EAA with Sharpcap, and I've found that some of the most enjoyable targets are regions of the sky with multiple galaxies in them. The best examples are things like the Virgo, Perseus, or Coma galaxy clusters, along with more distant and smaller-looking galaxy clusters like the Abell clusters.

Although the question of the distance to a galaxy gets complicated, due to the different ways to calculate distance (and their dependence on the parameters of any given cosmological model), I would assume the redshifts are pretty well known, and not open to a lot of dispute.

I would really enjoy being able to image a multiple-galaxy field, maybe with some quasars too, and see what the redshifts of the objects in the annotation are. At present, I often look to see what is the faintest-looking object I've managed to capture in the field of view. It would be neat to have the redshifts listed too, so as to see what is the most distant object I've captured. This would also be interesting if the user were looking at a small galaxy group (like the NGC 7331 group and/or Stefan's Quintet), in which one or more of the objects may not be a member of the group, as suggested by its redshift being different from its "fellows" in the FOV.

I can imagine this might require a live internet connection in order for the Deep Sky Image Annotation routine to fetch the redshift data.

This would be very nice during EAA public outreach sessions, because I could explain what redshift is, what Hubble's law is, and the public and I could inspect the annotated image to find the most distant object visible in it.

[admin]

Hi,

it's a really interesting idea, but I think it would be best handled by creating a custom catalog for use with annotation that would have the data built into it. Custom catalogs are documented here - https://docs.sharpcap.co.uk/4.1/#Custom ... %20Objects - and I would imagine that it would be possible to include the redshift in perhaps the second field (names), as SharpCap will display that onscreen for each target.

As far as I can see, since the built in catalog in SharpCap contains NGC/IC objects, which are generally relatively bright, so they will have a limited range of redshifts (this article suggests NGC1262 is one of the most distant with a redshift of only 0.1 - https://en.wikipedia.org/wiki/NGC_1262)

cheers,

Robin

[Cey42]

I have two feature requests:

1 - In the "Objects In View" tab, adding another column which is "Catalog." Tells you which catalog the entry came from.

2- A checkbox in the Settings tab, which is "Show All". This would show all the labels. Right now it appears that SharpCap tries to not have overlap in the labels, and if there will be it does not show it. I would like all labels to be shown without regard to overlap.

Thanks,
Cey

[admin]

Hi Cey,

Adding another column shouldn't be too much of an issue (but I will have to make sure that it doesn't force the horizontal scrollbar at the bottom to show by default, otherwise those who don't want the column end up being affected by it - a narrow default width might be best).

The intended way to see more objects when they are being pruned due to possible overlap is to zoom in - that reduces the overlap effect until you see what you need without text all over the place. I don't think the way that the labels are added is capable of coping with thousands without making things unresponsive.

cheers,

Robin

[Cey42]

Thanks for looking into these two requests.

As to zooming in, that does not solve my issue. I am frequently looking at Arp and HCG. And I want to know the names of the galaxies within them. But since they overlap, I cannot see them all. See these images. I understand the potential issue, if there are hundreds/thousands of labels. Maybe you could have a cutoff. Say if there are less than 100 labels, then one can show them all.

In this example, I want to see with the ARP and NGC label. Not the best example since they will 100% overlap but as long as they don't have the same center, the overlap would not be complete.

SC1.jpg

SC2.jpg

THanks,
Cey

[admin]

Hi,

OK, thanks for the further info - will have to give that one some thought.

cheers,

Robin