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Please, help with observation plan

by Schmetterling
Tags: observation, plan
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Schmetterling
#1
Nov15-12, 05:12 PM
P: 31
Hello!

How do you prepare observations at profesional telescopes?
How many objects it is possible to observe during one night?

I have to choose an observatory and prepare a proposal (as a homework) and I would like to receive guidance on the steps to follow.

Thanks! :-)
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turbo
#2
Nov15-12, 07:28 PM
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Have you dealt with any observatories before? If you are looking to jam a bunch of observations at the same wavelengths into one session, you might be able to get the operators to slew from one target to another. If you want to observe objects in a variety of wavelengths, you'll have to budget for sensor-changes, and that eats up the operators' time changing instruments.

Since this is homework, have you looked at the rules regarding homework, and can you show your work? Not trying to be a wet-blanket, here, but you really have to show your work and previous effort.
stargazer3
#3
Nov15-12, 11:31 PM
P: 44
Well. There's a lot to consider!

In general, it depends very much on what telescope are you going to use. Go to it's webpage, read the operation manual, and check if they have the exposure calculator.

You should prepare a list of objects you want to observe, and check if they are going to be visible frem that particular telescope at that particular time. Then, use something like this this to plot the visiblility for each object. Keep in mind that the higher the target above the horizon, the better.

Then calculate the exposure time based on object's magnitude and type. For example, if you want to get a pulsar light curve, then you'll need a lot of pictures with same exposure, so it can take a while to get one light curve out.

If you want to get a color image, then you need to use different filters for the observation, so that you'll get separate images for your R-,G-,B- channels (which also means that is takes at least 3x time to make a colour image than a to make a greyscale one).

Last, but not (oh no no no) least, check the field of view of the telescope! It could happen that the object you're trying to see will not fit in telescope's field of view! So if you want to shoot star clusters, galaxies, or nebulae, pay atention to their angular size.

As you can see, it's not that easy, and there's no answer to "How many objects it is possible to observe during one night?"

Disclaimer: I've only used a professional telescope once. It was fun, but I didn't write a proposal for it;)

P.S.: and YES, please DO post more info on what you're going to use/observe, etc.

Chronos
#4
Nov16-12, 01:01 AM
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Please, help with observation plan

It takes time to prepare for an actual observing session. You must identify the scientific objectives, target[s], data to be collected, filters, receivers, data storage requirements, and other such mundane matters. By the time you get to actually using the scope, most of the heavy lifting is already done. Of course, scope capabilities are an important consideration - FOV, limiting magnitude, etc.
Schmetterling
#5
Nov17-12, 05:33 PM
P: 31
Hello all.

I never have dealt with any observatories, and never have used a professional telescope!

My proposal should be for getting optical spectra for an object or list of objects (and to have some other for backup). I know it is needed to take sky- and dome-flats, calibrations with lamps and with other astronomical objects, but I don't understand how to do that. How to choose calibrators (stars?)? How to do calibrations?

I also know that best places to observe are in Hawaii, Chile, California, Arizona, Canarian Islands, Australia... Until now I have visited webpages of San Pedro Mártir, Gemini, & Cerro Tololo.

I liked planetary nebula IC3568, but it is too northward and found little information and doubted about what other (nearby??) objects could include in my backup list, so better I changed it for something else. Then, I searched info about Eta Carinae and it seems to be a good target. I'm looking for other interesting objects for backup...
Schmetterling
#6
Nov17-12, 09:06 PM
P: 31
I read that each insrument comes with its own lamps, its ok!
I'm very tired, it's time to go home...
stargazer3
#7
Nov18-12, 08:48 AM
P: 44
Quote Quote by Schmetterling View Post
My proposal should be for getting optical spectra for an object or list of objects (and to have some other for backup). I know it is needed to take sky- and dome-flats, calibrations with lamps and with other astronomical objects, but I don't understand how to do that. How to choose calibrators (stars?)? How to do calibrations?
Hmm... Schmetterling, I thought you only need to write a proposal, not carry out the observation. You need to submit it to the observatory and then do all the work, right? If so, you probably shouldn't look for the big observatories, 1m and below will suit your purposes well enough, unless you're doing "cutting-edge" astronomy. Find a telescope, and read through the manual (again, usually professional observatories have manuals). It should answer most of your questions.

Hey, you should've told us that you need to get spectra for your project. The easiest spectrum you can get is a star spectrum for a star, or a group of stars. You'll be able to determine star type based on the absorption.

EDIT: I still feel that the info on your project is unclear somewhat. Can you describe it in a more specific way, please?
Schmetterling
#8
Nov18-12, 05:36 PM
P: 31
Ok. Sorry if I was not clear. My hw is:

"Write a spectroscopic proposal for any professional telescope, including list of objects & backup, justification and feasibility, duration of observation, features of the instruments (spectrograph, gratings, filters...), calibrations... Specify what kind of instrument is more suitable for the chosen object." :-s

I don't have to go to make the observation nor submit it to the observatory, only to the teacher.
stargazer3
#9
Nov18-12, 09:50 PM
P: 44
There are probably the telescopes you can work with. Go to thier webpages, look for spectrometers, and read the manuals for them. You don't need a large telescope. Each telescope has coordinates, this is your constraint on the position of the sources. For 1m telescope star photometry you'll probably wan't visible magnitudes of below 10, but then again, it depends on a telescope.

Here's a 1-m telescope with a spectrograph which seems to be an example of what you're looking for. Take your time reading through the materials on that webpage.
Schmetterling
#10
Nov19-12, 10:45 AM
P: 31
:-D Thank you very very very much!!!! I will see the webpages right now!
Schmetterling
#11
Nov19-12, 02:30 PM
P: 31
What is the meaning of "Mdist." and "Mill." at http://catserver.ing.iac.es/staralt/index.php webpage?

And "The Nickel Telescope is available to the University of California astronomical community by subscription" --> isn't it available to any astronomer?
stargazer3
#12
Nov20-12, 12:36 AM
P: 44
Sorry, I can't see it. My guess is that Mdist. is a Moon distance, an angular separation between the Moon and the object. Mill.? Can you post a screenshot of where you've found it?

As for the second question, I think it is available.
Schmetterling
#13
Nov20-12, 08:49 AM
P: 31
Of course!
But IC3568 couldn't be observed due telescope's limits...
Attached Thumbnails
starobs.png  
Schmetterling
#14
Nov20-12, 08:57 AM
P: 31
Ohhhh!!! I know!
If "Mdist." is a Moon distance, then "Mill." is Moon illumination!

But, Mill = 80% at optimum observability??? :-s
Drakkith
#15
Nov20-12, 04:11 PM
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Quote Quote by Schmetterling View Post
But, Mill = 80% at optimum observability??? :-s
Yeah, the Moon will be 80% illuminated on 30 Mar 2013, which is the date in your attached picture. Which means it's a bad time to observe deep sky objects due to light pollution from the Moon!
Schmetterling
#16
Nov20-12, 07:18 PM
P: 31
But it's supposed that the webpage gives the best date for observing! ¬¬
I have changed date, haha.

And also, what objects' spectra could I obtain if weather conditions aren't good? Not M87, I guess...
Drakkith
#17
Nov20-12, 07:35 PM
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Quote Quote by Schmetterling View Post
But it's supposed that the webpage gives the best date for observing! ¬¬
I have changed date, haha.

And also, what objects' spectra could I obtain if weather conditions aren't good? Not M87, I guess...
I expect that the catalog just tells you the best date for the target in terms of how long it is going to be visible for that night. You would probably be fine in choosing a date at any time within a month or two of March.
Schmetterling
#18
Nov23-12, 05:38 PM
P: 31
Yes, I think so.
I changed date, now it is ok :-)


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