How to arrange a to-do list of targets

I faced the same challenge with a three-step process. First, make a list of your bookmarked targets. Second, download the iPhone app Observer Pro. Enter each target, one at a time. Observer Pro will tell you which months are optimal for your location for each target. Third, make a graphic spreadsheet with months across the top and a list of months down the left side. For each target, highlight in black the months it’s optimally visible.

Just doing RA and Dec is not the most effective way, as it is challenging then to figure out when it is actually high in the sky. My own organization is very manual in Excel. I have a group of rows in Excel for each target. When I see a target on AB or elsewhere, I generally go to Telescopius, which is free with a donation suggested, to find when a target is best placed for me. Telescopius allows you to even put in a custom horizon, so you can see when you are blocked by trees or houses, etc. And it shows you your FOV, so you can plan your FOV placement.

Below is an example for M97 which I’m imaging now. From Telescopius I put in a start date when it is high enough in my sky, and a finish date when it is too low. In this case I can start late on Feb 1, ending June 1, with a maximum of 4 hours on both sides of the meridian. I often use 45 degrees for many targets as the minimum, but those in the northern sky I can’t start until about 60 degrees altitude due to trees. For low lying fruit in the south, I try to setup the altitude so I can get 2 hours each side of the meridian. Here for M97 it is a maixum of 4 hours each side of the meridian, but by June 1, I noted my capture ends at 12:25, so only 2 hours is possible. I put a D for a dusk start, T for a transit, etc. so I understand what is the limit. I copy images from AB into Excel as best examples, along with relevant info so I know how difficult a target it is, what conditions/filters I might need, and what a great image looks like.

I simply organize each target in Excel first by Start date an end date. I start my table in January and work through the start dates to order them. If many targets have the same start date, I put the one with the earliest end date first. It is very easy to slot a new image in, once I know the start and end dates.

Note Telescopius can put the moon in as well, and tell you when it is okay to image around the moon with various filters, so I do check that before I go out to image.

I also add other info, like what filters I might need, and other information as needed. This includes information on my own image of the target, so I can see what I need to do to add to it, or if I’m happy with what I have.

📷 image.pngSo if I want to start on a certain date I scroll to that start date and look at what I might want to do, and when that ends. I then look at what I might do next, to make sure I have something to fill in, generally I need 2 to 3 targets to fill a full winter night, and also backups in case of a moonlight issue.

It is manual, though one could create groups and do fancy auto organization in Excel. The advantage though is that I’m not caught doing a target that is sub-optimal.

Rick

I use Gary Imms Deep Sky Compendium spreadsheet. It has columns for setting a target as a priority or not, whether it is planned, in progress or complete. His spreadsheet is very comprehensive, you can set your location and it will show you rise and set times plus a heap of other information. Its become my go-to planning tool. It can be found at COMPENDIUM

📷 Image1.jpgSo I faced the same problem of deciding which objects to image on any given night, I went to chat gpt, i told it my lat, and long, and asked it to make a list that shows when the messier objects are at their zenith, I won’t go into the specifics of my request the image details nicely all the relevent information, once I have imaged an object I write an asterisk next to it with a date. This is not a be all and end all, you obviously can image these objects weeks before and after optimal, it just gives a nice handy glance at the season and month, you could also take into account obstructions say exclude the first 20 degrees above horizon for a blocked southern aspect. hope this helps.

Fascinating result. Did ChatGPT actually generate your spreadsheet, or just supply a data list that you entered?

CS. Bob

CS, Bob

Robert Gillette · Mar 13, 2026, 01:40 PM

Fascinating result. Did ChatGPT actually generate your spreadsheet, or just supply a data list that you entered?

CS. Bob

CS, Bob

Hi Bob, it was kind of a combination, chat gpt, produced a csv i then put it into word tables. it ws not completely correct and had missed the odd comma but to be honest when you populated the document I found the columns went out of sync putting the comma back in fixed it. it’s worth noting that chat gpt was able to advise on how to set up tables making the whole process reasonably easy. but yes it was basically cut and paste from the AI output. I do like the paper version where i can sit there and run my finger along the column, obviously when I get the scope out I then setup the scope in Nina and pick the objects out of the list, and track and sequence as normal, it does mean I know what I want to image before I go out

Hey all,

Here’s a website I’ve found useful:

https://iris-observability.lam.fr/

You can get all this with Telescopius, true, but it can get lost in a lot of clutter; this has a very simple interface. You put in an object (and your location), click “optimal” and it shows the graph for the best night. Then you can easily go back and forth by day and choose the optimal date for you (eg, accounting for moon, whether you have east or west exposure, etc.). I put that in my Notion database and then sort all my objects by optimal date.

-Dean

Bonjour Leonardo

D’abord il faut connaître ton champ visuel de ton capteur FOV pour bien composer ton image car ce n’est pas tout de centrer un objet car souvent il vaut mieux de choisir une étoile de référence et d’entrer ses coordonnées. je m’explique.

Premièrement utiliser le compendium de Gary Imm https://www.garyimm.com/compendium

Deuxièmement j’utilise l’application skysafari pro https://skysafariastronomy.com

Je choisi mes cibles dans le compendium, je crée un liste dans skysafri de ces objets ET compose mon image selon mon FOV et orientation de la caméra. je choisi l’étoile la plus proche du centre de ma composition.

exemple je veux imager M81. je m’aperçois qu’il y a un autre objet, M82 tout près. alors avec skysafari je compose mon image et trouve l’étoile qui fixera le centre de mon image. M81 M82 T.TYC 4383-0698-1 90°. 90 degrés étant l’orientation de mon capteur. 09h 56' 02" 69º 18' 32" étant les coordonnées de l’étoile que j’enregistre dans mon logiciel de contrôle de ma monture, dans mon cas ma liste du ASIAIR que j’utilise.

en complément je dois choisir le moment propice dans l’année selon mon horizon disponible. Dans mon cas l’azimut est de zéro à 180 degrés et l’altitude minimum est de 30 degrés. Le reste est parsemé d’habitations et d’arbres.

Dans le compendium il y a des filtres qui permettent de préciser le tout.

Il reste à transposer tout cela dans le fichier en ajoutant une note.

Gary a fait un travail colossal et il est gratuit. merci Gary! https://www.astrobin.com/users/GaryI/collections/

Bien entendu je recherche des images dans Astrobin qui vont me permettre de composer l’image finale

Bon ciel!