Order In Which To View Objects During a session

[Jiggy 67]

Hi all,

Been away for a while due to work commitments and such like, in fact i'm ashamed to say that it's been more than 18 months since I last got any of my scopes out 😮‍💨 but I intend to do a lot more observing over the coming season, starting with a trip to Wales where we have recently bought a new static caravan under far darker skies than I enjoy at home.......I've booked a few days off work either side of the New Moon on 13th November and I intend to go purely for the purpose of astronomy....so the wife is staying at home with the dog...just me, the scope and a bottle of fine scotch whisky (and the odd Indian takeaway).

In preparation, I am putting together an observing list on SkySafari 6 Plus which includes, almost exclusively, of objects i have never been able to observe from my light polluted skies at home, the remnants of the Messier catalogue (those available in November), some globs, and my personal favourites, quite a few fainter planetary nebula. I will probably revisit some old favourites and get some coloured doubles in as well.

As most of those who use SkySafari know, you can order your observation list in a number of ways, in fact, quite a number of ways, and I've never really got my head around the best way to do it, examples are "Transit Time", "Rise Time" and "Set Time". 

I want to organise my time through the night to maximise the best time to observe all the objects in the list in the best possible order (we're talking GoTo by the way)...so......what is the best option for sorting your list, Transit, Rise or Set???.....I won't even mention all the other options in the list, declination, azimuth, ascension etc 😖.......although "Altitude" might be an option.

Opinions please

 

[Stu]

Starter for ten….

Objects are highest at transit, so aim to observe them as the cross the meridian.

But…. Those that are already past the meridian and heading towards setting you will need to pick off first before they disappear.

There is an app called Observer Pro which has great graphs showing when objects are at their best, might be iOS only.

[Jiggy 67]

Thanks @Stu.....luckily, I am also IOS only!...I will have a look at that app. I was already thinking that it's best to order objects as per "set" as that will cover everything that comes before the "set" time...I'm thinking "set" will come first, followed by "transit" and then "rise".........sometimes you just need someone to confirm your thinking.

[globular]

I think your best bet is to invite me along and I'll give you a hand 😁

[Jiggy 67]

7 minutes ago, globular said:

I think your best bet is to invite me along and I'll give you a hand 😁

It's amazing what happens when you mention Scotch Whisky!

[John]

You have already had some good advice. All I will add is that I always try and finish on a couple of "easy" targets rather than something too challenging. That way I end a session in a positive frame of mind 🙂 

[Jiggy 67]

2 minutes ago, John said:

You have already had some good advice. All I will add is that I always try and finish on a couple of "easy" targets rather than something too challenging. That way I end a session in a positive frame of mind 🙂 

Absolutely...theres nothing worse than going to bed having failed on your last couple of targets. 

[globular]

41 minutes ago, Stu said:

There is an app called Observer Pro which has great graphs showing when objects are at their best,

@Stu Does this app let you create a list of best items, sorted by best order?  A bit like SkySafari Observing Planner?

And can it then be exported into SkySafari?

[I'd try myself, but it's £13 and I'd rather know before I buy]

[bomberbaz]

9 minutes ago, John said:

You have already had some good advice. All I will add is that I always try and finish on a couple of "easy" targets rather than something too challenging. That way I end a session in a positive frame of mind 🙂 

That is a rather obvious but brilliant piece of advice. Too often I have finished after an unsuccessful hit attempt at something difficult and thought, " what the hell, home time".  Better to  think, "wow, that was good, time to head back".

thumbs up!

[Stu]

7 minutes ago, globular said:

@Stu Does this app let you create a list of best items, sorted by best order?  A bit like SkySafari Observing Planner?

And can it then be exported into SkySafari?

[I'd try myself, but it's £13 and I'd rather know before I buy]

I added some random objects to the observing list, then it lets you sort them by, say, transit time or a number of other parameters

[Jiggy 67]

@Stu That's pretty simple, I take it the green is telling you the optimal time to observe?? 

[Stu]

19 minutes ago, Jiggy 67 said:

@Stu That's pretty simple, I take it the green is telling you the optimal time to observe?? 

Yes, orange is visible, green is good visibility, thickness represents altitude. It takes into account the moon’s phase and position, and you can click in to get more detail.

Note that I don’t think there is a way of exporting the list to SkySafari unfortunately.

Another useful feature is being able to map your local horizon (including trees and houses etc) so you can see when things will be visible. This can be exported and then imported to SkySafari which is useful.

[globular]

@Stu sorry for all the questions - but here's two more

*  does it 'talk' to skyafari?  Import / export lists between the two?

*  I have my horizon plotted in skysafari - but it only seems to display it, as far as I know it doesn't interact with it... i.e. know if objects are visible or not.  Does Observer Pro use your custom horizon to 'know' what's visible?

 

edit:  you answered them before I asked them. lol

Edited October 27, 2023 by globular

[globular]

The sorts by 'hours of good visibility' are great for imagers - who want to leave their kit capturing data for as long as possible.
Sorts to help visual observers, of the kind @Jiggy 67 and I are looking for - i.e, what's the best order so I don't miss anything really good - seem a bit limited.
I think I'll continue to create and sort lists in SkySafari - but manually tweak things based on Observer Pro visibility information.

Great info @Stu - thanks 

[Zermelo]

I suspect you may want to switch between different orderings, and at least that's not difficult in SkySafari. Of course, some orderings for a list (e.g. RA, transit time) stay constant, while some (Az, Alt) may change with the sky, through the evening.

One consideration that I have when observing at home is wanting to minimize slewing noise. I also like to start a session with the targets that are closest to my final alignment star, hoping for better goto accuracy, and then work away from there. I find sorting by azimuth to be quite convenient for this, but these considerations may not be important at your remote site.

Like you, I have a small handful of Messier objects still to bag, all of which have low declinations. If you have an observing list with several of these, then sorting by transit time, for part of the evening at least, may make sense. Of course, the transit time for any individual object is available in the Object Info page, and don't forget that the Graph Object option shows the altitude curve for an object across an evening.

@Stu makes a good point about some objects being more urgent due to their being lost in the West. My observing lists usually include a couple like that, targets from the preceding season that I hope to catch early on in the session. Sorting by set time is the obvious option here, though azimuth can be an acceptable proxy.

The point about avoiding obstructions can be also be important, though possibly not so much in a rural field as in a back garden. I have significant obstructions at my home location, and it's a pity that the horizon feature in SkySafari is for display only. If I have a long observing list for an evening, I sometimes use the list's comments section to note in advance the best times for targets that will be affected adversely.

Finally, if you're switching between different sort orders for a larger observing list during a session, I find it very useful to apply the "Unobserved in this list" filter, to exclude the ones you've already been to (though in my experience it can sometimes fail to exclude objects that have been observed; there's a bug that I've not been able to pin down yet).

[Stu]

It’s a shame that you can’t export lists from Observer Pro as it does generate useful ones. Looking at it, ranking by Hours of good visibility seems to give the most useful results vs transit times.

The visibility calculation does take into account the local horizon you’ve generated (unlike SkySafari) so that helps cut out any objects that aren’t visible from your location. It factors in surface brightness and the Moon’s brightness and altitude into the visibility equation so is at least applying some logic to the visibility.

I think the best thing is to use it as a planning tool then but build your lists in SkySafari still. Hard to say if it’s worth £12. I bought it a long time ago but would say I use SkySafari a lot more still. 

[Zermelo]

Getting more speculative now, another (lesser) consideration might be to sequence a list of targets to minimize the total slew, a kind of celestial travelling salesman algorithm.

I expect it won't be too long before planetarium apps feature a real-time interface to your AI of choice, which will incorporate all of these considerations, produce an optimized schedule based on them, and then drive your scope for you.

[globular]

It could do the observing for you and write up an observation report for you to read in the morning. 😄

I typically use the option in SkySafari to display my observation list on the map and then hop from one to the next nearest, rather than use the order they appear in the list.  This limits slewing - but I do miss some objects because they are gone before I get to that part of the sky.

Doing a combination of all sort of different techniques is the best we can do.

[Jiggy 67]

1 hour ago, globular said:

 This limits slewing - but I do miss some objects because they are gone before I get to that part of the sky.

Exactly the reason for my original post. Don’t add over slewing into the mix!! 😩 As I’m using a reflector, not only do I have to think about the order of observing but also where the eyepiece is going to end up after slewing!!

[globular]

I still think we'd be better off working this through together.  I have a rather nice bottle of brandy we could ......    😇

[bomberbaz]

On 28/10/2023 at 12:13, globular said:

I typically use the option in SkySafari to display my observation list on the map and then hop from one to the next nearest, rather than use the order they appear in the list.  This limits slewing - but I do miss some objects because they are gone before I get to that part of the sky.

How do you do this? I use SS6 for pretty much all my observing these days and often cram a bit too much on my lists so having them displayed on the map might help me be more organised and structured in my viewing whilst saving me printing off a list that often ends up sopping wet in dew.

[globular]

3 minutes ago, bomberbaz said:

How do you do this? I use SS6

I'm on SS7 but I think I remember it was in 6 too (although possibly activated differently than as below in 7).

When in an observation list, you select "highlight objects in SkyChart" ...

[John]

I'm very impressed at how organised and systematic people are about planning observing sessions 👍

Makes me feel a little guilty for my rather casual approach 🙄

I might have one of two targets in mind but after that it's whatever takes my fancy. Typical "space tourist" 😉

 

 

[bomberbaz]

8 minutes ago, globular said:

I'm on SS7 but I think I remember it was in 6 too (although possibly activated differently than as below in 7).

When in an observation list, you select "highlight objects in SkyChart" ...

Can't seem to find this option, the help menu makes no mention of it being available but I assume 7 has the option needed for my dobs DSC to work.

I will upgrade to SS7, seems a more sophisticated option, hope I can share my lists.  Think I have seen mention of this somewhere in help menu.

[globular]

@John You have years of experience and knowledge to draw on.
I'm a space tourist that only has 3 years under my belt - so I need all the help I can get.

That said - and as this thread attests - I make a list of likely objects to observe but only ever observe few of them before getting distracted by something else and going off piste.