Frequently Asked Questions

How do I initiate the guiding mode and select a guide star? Where are these options located in the control program? Thanks for modifying guiding system. I would really like to try some longer exposures, particularly with the SII and OIII filters.

There are 2 links to the guiding. One is in the centering mode. (See video’s on centering and guiding) Also there is a link from the sky chart page called guider.

The main concept here is that you are using an internal guider. This means the filter will not only cover the main sensor but the guiding chip as well. When you arrive at the guider page there are several parameters you can select in preparation to selecting a guide star. The duration by default is 5 seconds. However if you are going to use filters especially narrowband filters you may wish to change the duration to 20 or 30 seconds. In conjunction you should also select the densest filter you will be using in the exposure series. The aggressiveness at 5 is usually sufficient. I would also leave the delay at zero as well.

When you start the actual guide star sequence the filter you selected will temporarily move into position during the select guide star exposure. The camera will then take an image through the guiding system and display an image that was actually taken through the specified filter. This allows you to select a guide star as it will appear when images are taken with the filter in place. So if the 20 or 30 second integration time is sufficient you will be able to select a good guide star. Since the guider has been binned the guide chip has had its sensitivity enhanced and the guide stars will not only be more intense but better defined as well.

I have read about your service and I have already browsed your webpage. Some questions have been unanswered to me. When do the scopes get closed in the morning or opened in the evening, e.g. comets are always near to the sun?

We open around twilight and close around dawn. For instance at the moment we are opening access to the scopes at 9:00 PM MDT and closing around 5:00 AM. Of course this varies through out the year. We can also adjust the schedule to accommodate any requests from users. We are very flexible and accommodating.

How far do the telescopes get to the horizon, due to low objects. Maybe 10 degrees above the horizon ?

Our normal horizon is around 20 degrees. We can actually go below that to about 15 degrees for special events or be request. The walls of the observatory are the limiting factor.

How do you count the used time ? Is it the time I'm logged in or the time I'm exposing an image

Your account is charged from when you log on until you log off. There is a special auto-logoff feature in the software that allows the system to log you off after a series of images or after the completion of a script that might have been run by the user.

Notice that we provide a separate high-speed FTP server for storage of your images after your session ends. There is no charge for the time you spend downloading your files.

I am a total newcomer to astronomy - scared away by sleepless, cold nights. Your offer together with 8 hrs time difference shifts this nocturnal activity to after breakfast. Exactly what I have been waiting for. I am about to sign up for the newcomer package but I have some questions which are not answered in the FAQ.

How long is my purchased time valid? It expires after a month/year/never?

At present 2 years after the date of the last purchase. The exception may be special packages that have expiration dates noted.

I understood that the moon and planets are too bright. As a newcomer I am not 100% sure if the telescope will always point to where I think it points to. Is there a risk of doing damage to the equipment or is there a clever software protecting it from me?

You can not damage anything as a result of your operations. We look after you at Rent-a-scope. :>)

When is the best observing time (except for weather conditions)?

This depends in which type of astronomy you have an interest. If you would like more input I will be happy to call you so we can discuss in depth. Of course you can observe anytime the observatory is operating which is during the dark periods in New Mexico.

Browsing through the fotos I noticed considerable variations in the exposure time, in particular when filters where used. Is there some technique to estimate the exposure time or is it pure try and error?

We suggest you start by using the times published on the pictures. The filters are generally much denser than the clear filters and therefore require more exposure. There are no right or wrong answers. Feel free to experiment.

Legally, who owns the data I produce? On a similar site the conditions stated that the data are owned by the site owner, not me, and I get a non-exclusive right to use them. How is this in your case?

Our policy is that you own the data completely. We just act as a vehicle by which to accomplish your astronomical missions.

I am interested in trying it out. So I buy 10 hrs and then what? Do I reserve time on one of the setups or is it first come, first served?

When you sign up and pay for your time you are then provided access credentials in the form of a userID and password.  Also you are provided with a URL for the scopes.  You can elect to schedule time at an added charge or use the system when ever it is available on a first-come, first-served basis. Scheduled time takes precedence over available time.

I assume the setups are all drift aligned?

The setups are both aligned with T-point.

Is there an automated focusing routine or is it a manual process? 

We take care of focusing.  There are temperature compensated focusers on each system.

I'm used to using a separate autoguider. If it's an SBIG camera, how do I find a guide star?

We have separate guide scopes and guider cameras on the instruments that require guiding.

Do you have saved dark files or do I pay to take my own?

We provide master calibration files for standard exposure times 10, 30, 60, 120, 300, 600 second dark frames, bias and flats.

I assume there's a way for us to set the cooling temp?

Cooling is set year around at -10C on systems using SBIG cameras and -25C on our FLI cameras. 

Are there optional focal reducers for any of these setups?

No optional focal reducers but we have several different cameras to install to give different resolutions.

How do I watch for passing clouds? Do you have an all-sky cam I can watch?

Yes. There are two cameras normally operating

What is binning (bin) in conjunction with the CCD camera?

Binning is a type of configuration that controls the sensitivity and resolution  of the camera’s sensor. In the case of the ST8XE for instance, each pixel is 9 microns square. If you were to select bin 1 then the camera would use each separate pixel to take an image. This is the highest resolution mode but the least sensitive. Bin 2 would electronically join 4 of the pixels to form a new apparent pixel of 18 microns square. This would be 4 times more sensitive than in the bin 1 mode but produce less resolution (image might become easily pixelated upon enlargement). Bin 3 (maximum suggested binned mode for this camera) would produce 27 micron square apparent pixels that would be 9 times more sensitive but again with lower resolution.

How can I tell if it's clear there? I saw your Clear Sky Clock; I find those to be pretty accurate around here (Boston area). But I'd hate to get all ready to go and then have a cloud/transparency problem.

It only takes a few seconds to sign on and off if conditions were not permitting.  We generally notify you (distribution list) of conditions.

Is dewing a problem there? Do you have some kind of countermeasures?

We are in the desert.  It's very dry. However there are times when moisture is present. We have automatic sensors that close the roof when ever the weather is threatening.

Would I operate it remotely??

You operate the system remotely.  Usually I'm in the background in case there is a problem (very rare)

When I'm using my paid time, does it go by the nearest minute or once I start another hour then I need to try and use it all?

Use it at your pleasure you are only charged by the portion of the minute you use.  The exception is scheduled time. This you must use per your scheduled time.

Is it always available? What about on holidays?

When ever it's dark in New Mexico 7 days a week, weather permitting.

I think this is a great idea. When you consider the cost of the setup, and how many hours I'd be using it here in the northeast if I bought it all myself, my price per hour would probably be much higher.

Where is the observatory located? 

• Time Zone: GMT -6:00 New Mexico, USA.
• Mountain Standard Time - Daylight Saving Time Observered
• Latitude: 32° 54' 14"
• Longitude: 105° 31' 44" West
• Elevation: 7300 Feet

This all sounds confusing; just how difficult is the system to operate?

First let me reassure you that the idea of operating Rent-a-scope sounds more intimidating than it really is.  For the basic operation, all you have to do is type in a few characters like m31 or m13 or NGC891. 

The scopes operation is almost fully automatic.  If you request it, I'll be on line with you, real time, using the Yahoo Messenger, for the first few times you use the system to help you through the few settings that you might find confusing.  There are only a few settings even in the more complex LRGB mode.

Placing an order for time allows you access the system to view the help files that explains the whole operation.   

Can you view the planets and the Moon?

Our scopes are generally set up with a high speed very sensitive CCD cameras mounted at what is known as prime focus or Cassegrain focus. This normally means the cameras are mounted with out any supplementary lens or optics in the light path. This allows our cameras to yield high resolution images of faint fairly large objects using short exposures. 

Our systems are way too sensitive to capture a planet or even the Moon. They are also configured in the current mode to acquire images of deep space objects. 

On Saturn if you were to use the Ha filter (the most dense) you would have to use a shutter speed of .03 seconds. Using the Ha filter would also require you to refocus since the filter is not par-focal with the rest of the filters. When you finally did get an image it would be too small to see any detail. 

We can, however, shift gears and do what is known as eyepiece projection or insert a Barlow lens or both.  This allows us to greatly magnify the image and present a smaller field of view  but larger image.  This would allow us to do fairly large images of the planets. This setup would be somewhat limited in that only the planets and Moon, (separate craters would be difficult, if not impossible, to point at with our current system.

Changing configurations is not too much of a problem except that when we adapt an instrument to planetary work we may have a lot of overhead necessary like running new calibration frames and a pointing model to make the telescopes point accurately enough to capture the position of the planet at high magnification. 

The point of all this discussion is to point out that additional time for set up requires a cost offset so there might be a an additional cost to the normal $65 per hour usage fee.  Also it would make a lot of sense to me if we did this you would probably plan to purchase a few hour block of time to maximize the set up fee.