2.3 Requesting an image from COAST
Using what you have learned about how to use the RA of an object to determine its visibility, you are now in a position to pick a suitable object and plan your first observations with COAST.
In this video Alan will give you an example of how to request an image, which you will be doing for your own image in Activity 4. Jo will then follow the progress of that image request with COAST on Tenerife.
Download this video clip.Video player: boc_aot_1_video_week4_2_requestin-image.mp4
Transcript
MALE INSTRUCTOR:
This week, you'll be requesting your first images from COAST. So I'm now back at Milton Keynes, at my desk. And it's a horrible, grey day. But I'm going to be requesting my images the same way that you're going to request them, using the telescope.org interface web page.
So here I am on telescope.org. I'm on the main page. And to request some images, I'm going to come down to Use Telescope on the menu on the left-hand side. So in Use Telescope, it's asking me to select a target. And the object that I'm interested in is the Great Orion Nebula. And I've got my notes here. And that's telling me that the Orion Nebula is Messier object 42, M42.
So I can go ahead and enter that. And COAST knows about the common Messier objects and the common objects. So I can just enter that by name. If you're interested in a different object, then we can click to enter the coordinates explicitly of any object to tell the telescope to point to a specific right ascension and declination coordinate. But for the Orion Nebula, that's such a well-known object, I don't need to worry about the exact coordinates. I can go back to enter the name, M42, which I'll go ahead and do it now. And it'll tell me this is Messier 42, the Great Orion Nebula. So COAST knows about that.
And I've got, on the right-hand side, a confirmation of the coordinates. So I can check that those are correct. And I've also got confirmation on the little calendar down here that this is a good time of year to observe that particular object. So I know it'll be well-placed in the sky.
So I've selected my object. Next, I'm going to go and just refine exactly what images I want. So we're on COAST. That's correct. And now I can select some different options for my images. So I can select what filters that I want and, most importantly, what exposure time we're going to use. And COAST will recommend for each object a recommended exposure time, which I'm going to use now. You may want to experiment with these exposures to get different effects. But to start with, there's a recommended value.
So for filters, I can select individual filters-- red, green, and blue-- or I can request a colour image, which is the first image I'm going to request. So COAST will then take the individual red, green, and blue images and combine them to form a colour image. And the other thing that COAST will do automatically is to take the calibration frames and apply those to the image. So I'm going to select a colour image, click on Next, and that's now selected. It's just confirming all the parameters that I want to image. Press on Submit to send that through to the queue.
So now I can go and view the images that I've requested. We can see I've got a whole bunch of ones that have already been completed. And here is my image of the Great Orion Nebula that's new on the queue. That will then go off into the overall COAST queue, where it'll be combined with everybody else's requests. And the next time the weather is clear, on a clear night, and my request comes to the top of the queue, then that image will be taken and will be waiting for me the next time I check back. So we'll check back in a day or two and see what's happened.
FEMALE INSTRUCTOR:
So back on the mountain, let's see what happens to Alan's observing request when it gets to the top of COAST's queue.
Oh, so we've got a nice, cold night out there, which is exactly what we need for observations. COAST will be looking at the weather conditions right now and trying to decide is it raining or not, is it too windy, is the humidity too high. And if it feels that the conditions are right, it will open the dome, which hopefully it will do any moment.
So as the dome opens up, the telescope will be busy as well. Its temperature will be adjusting to the cold air outside and the slightly increased in humidity. And the camera will be cooling itself on the back. It will also be looking through the list of objects that it needs to be targeting tonight to take your observations, and hopefully those of Alan as well. So we'll see what it goes for first.
So it's clearly picked its first target. We better turn the lights out.
MALE INSTRUCTOR:
It's now a couple of days since I requested my images. And I've been keeping an eye on the weather over in Tenerife. It seems there's been a couple of clear nights. So I'm going to come back to telescope.org now to see whether my images already.
So here we are, logged back into telescope.org on the main page. And I can see now on the dashboard that I've got an announcement, "You have new images." So the same thing will happen when you come to see your own images when your own images have been taken. So let's click on that and see what's happened. So here's my list of images. Click on the image there-- takes a moment to come up. Brilliant. Look at that. Fantastic.
Interactive feature not available in single page view (see it in standard view).
Activity 4 Requesting an image from COAST
Timing: Allow approximately 15 minutes
- First decide which of the Messier objects you want to observe. Use what you have learned about how the RA determines the visibility of objects at different times of year to choose an object that will be well placed for observing with COAST during the month in which you are doing this activity.
- Log in to the telescope.org website using the login information that you have created.
- Select Use telescope from the menu on the left hand side. In the Select Target box, enter the ‘M’ number of the object you wish to observe. For example, in the video, Alan enters ‘M42’ for the Orion nebula.
- Confirm that the details match what you expected. As shown in the video, telescope.org will confirm the visibility of the object. Check that this matches what you worked out in Step 1 of this activity.
- Next, you will be asked to select your Filter Options and Exposure Time. You will learn more about these options when you do some more advanced imaging later in the course. For now choose the Colour filter and accept the recommended exposure time. Click Next.
- The next screen headed Confirm Request lists the details of the image that you have requested. As shown in the video, if you have requested a colour image the Filter will be shown as BVR, and on this screen the exposure time is given in milliseconds so don’t be alarmed if it appears to have some extra zeros! (In the video, the requested exposure time of 180 seconds (three minutes) is shown as 180 000 ms).
- Once you are happy with all of the information, press Submit to complete your request. You will see a confirmation screen stating Request Submitted.
Congratulations! Your request is now in the queue. When it reaches the top of the queue the image you have requested will be taken the next time that COAST has clear skies. Depending on the weather in Tenerife and how many other images are in the queue it may take a few days before your image is taken, so please be patient and check back from time to time to see if your request has completed.