Simon Carr’s Blog

Both my self and my friend noticed that the nextstar 4se was very sloppy in altitude. When I tried to attache a Digital SLR to the telescope, the slightest bump would cause the scope to drop at the camera end. There is a very quick solution however, tighten the bolt on that holds the altitude axis. 

1) undu bolt that holds the wedge of the scope to the arm and take of the scope.

2 Keep turning this same bolt until it comes out. You will see behind it one of those nuts with the blue plastic inserts. This needs tightening up, I did not have to tighten too much, perhaps only a quarter of a turn to make it bite. 

3) Put the scope back on the arm and hey presto, you are ready to use the scope with a camera.

Hope this helps anyone who was starting to loose patience.

At last some clear skys tonight, but of course it didnt last! But there was enough time to try out my setup with the phillips web cam. I managed to get a short avi that I stacked in Registax with the following results.

The august weather for the past 3 weeks has been dreadful. If you are an astronomer and you live in the North West of England like me, you will be sick and tired of the cloud. Well, I just checked the cloud forecast on the BBC web site and it shows a break in the cloud for the whole of the UK for Tuesday night. It does not last though, complete cloud cover for the whole of the UK on Wednesday again.

I am looking forward to the nice cold crips clear nights of Winter, but don’t let me wife know I said that.

 Who said a small aperture telescope can not take deep space images. This is only my second attempt. I used a Celestron Nexstar 4 se with a Minolta Dynax 5D DSLR at prime Focus. No Barrow lens was used. IT was taken as a single 2 minute exposure.

When I first looked at the image, it just seemed to be a blue ball. I processed it by copying the image about 80 times and then stacking those images on top of each other in Registax. I know it would be better to take 80 two minute exposures, but I don’t have the patience for that. I then messed with the contrast, brightness and a few of the wavelets to get his image.

I don’t normally like doing this but 10% is a lot and I recently saved a bit of a wedge using the link.

If you are planning to buy from Boden, then click the link below to get to there site and you will get a 10% discount, Free Delivery and Free Returns.

IF you just visit the Boden web site you will not get the discount, you must use the link below.

You can download VMWare images of Ubuntu from the following site http://www.chrysaor.info There a load of different variations on different versions on ubuntu, both desktop and server.

I chose to download the image I had chosen by bittorrent and got 1MB sec

I will test the image and let you know how I find it.

I want to see if I can get better results with my philips web cam than I have with the DSLR camera. While the Minolta 5D has a massive CCD Chip it does does require that you take a lot of short exposures or a smaller amount of longer exposures. The problem with this is that the slightest error in tracking ruins long exposures and the movement of the mirror in the camera can vibrate the telescope. Taking shorter exposures reduces the problem of tracking being off, but means a long time waiting for all the exposures to be taken and the vibration remains a problem.

Using a USB PC camera can reduce the problems with tracking and since you are constantly recording the AVI and not waiting for the camera to process each image between exposures you don’t have to wait as long.

I am also going to start using a computer. I have an old laptop that I was hoping to use World Wide Telescope with http://www.wordwidetelescope.com, but it does not have a 3D Video card so it wont work. Instead, I plan to use ubuntu installed on VMware. I will use K Stars to control the telescope which I have had working in the past,  but have not tried it with VMWare. The problem may be getting VMWAre to see my serial port.

For the video I am going to give wxastro capture a try. I messed around with it and it seems quite good.

I will let you know how it all turns out, assuming we get a break in the cloud any time soon.

Regular readers of my blog will know that I have a nexstar 4se. I assume that this post is accurate for any nexstar telescope, but anyone who knows different, please let me know.

I wanted to share what I understand about the types of sync available on the nexstar controller.

Sync
This is used after you have done a goto, but find that the scope is not quite on the goto object. Sync will give you a relatively good level of accuracy in that area of the sky for future goto commands.

Preceise Goto
This command is a one time command and any correction used will not be saved by the scope. It provides the highest level of accuracy for the one object you want to view.

Alignment Stars
This command allows you to view, change or add to the stars that you used for the alignment. As an example if you used one star align, but then find that you are not getting very good accuracy, rather than doing a full alignment you can choose Alignment Stars and add a second star. This then has the same effect as doing a fresh two star align. This method gives a greater level of accuracy across the whole sky.

So you can see that each one is used for a different purpose. I tend to use the precise goto and the sync in combination. I will first use the precise goto to get an accurate lock on the object and then immediately do a sync on it, with out moving the scope.

Having just started out in Astrophotography I am still learning what works and what does not. I am currently using a Minolta Dynax 5D digital SLR prime focus.  But plan to start experimenting with my Philips SPC900NC USB Camera. Below are some of the lessons I have learned so far.

Prime Focus

This is achieved by connecting the camera to the telescope eyepiece or camera port by replacing the cameras detachable lens with a T Adapter. The Celestron Nexstar 4SE is a small telescope and this setup provides very little magnification, leaving you with small hard to resolve objects on the photo.

I am going to get a barrow lens and put this between the camera and telescope which should make for larger pictures, but I am not sure if they will be clearer.

Mounting on the eye piece or camera adapter

The celestron Nexstar 4SE has a camera adapter at the back of the scope. You can switch between directing light to the eyepiece or camera adapter at the turn of a knob which flips a mirror.

Mounting on the camera port

By mounting the camera on the camera port you restrict the amount elevation the telescope can achieve because the camera body hits the battery compartment of the mount. It dos give the advantage however that you can flick between an eyepiece and the camera. I am not sure how much advantage this has however, since the focus point is different for the eyepiece and camera, so you would need to look through the camera view finder to achieve focus again before taking a picture.

Mounting on the EyePiece

In this configuration, you get full movement in all directions with no snags. You are however limited to viewing through the camera’s eye piece between photos unless you wish to swap.

All in all I think connecting to the eye piece is a much better solution for large SLR cameras. Using a PC Cam does allow more scope for connecting to the rear camera port, but in test fitting my camera I have found that it will still snag when the telescope tries to look straight up.

Equipment Needed

If you are just starting up in astrophotography I would recommend you buy the necessary equipment to attach to the telescopes eye piece. For this you will need (with links to the products I purchased from Telescope Planet)

1) T Adapter http://www.telescopeplanet.co.uk/ViewProdDetails.asp?prod_code=PON08F000016

2) T ring to fit what ever camera you have. http://www.telescopeplanet.co.uk/ViewProdDetails.asp?name=Celestron%20T-Ring,%20Minolta&prod_code=PON06B000017

The T adapters are a universal fit. The T ring (in my case) has a bayonet fit for my Minolta camera on one side and on the other a thread to fit the universal T Adapter. I purchased mine from

I have had this telescope for about 8 months. I would have used it more than I have, had it not been for the large amount of cloud we seem to get in the North West of England.

When I first started using my scope I had a lot of problems aligning it and getting it to track accurately. When I started searching for solutions I found that most people were having the same problems. The only detailed instructions I could find were for the bigger celestron telescopes with the double arm fork. This post may help you if you are struggling like so many others out there.

Type of Alignment
1) I only use the EQ North Align. This seems to give me the best alignment and consistent goto and tracking.

Alignment Process
2) Position the telescope so that the hinge on the wedge is pointing towards polaris. Then set the tilt to your correct location on earth. (I used google earth to find mine)

3) Choose EQ North Align and make sure the location, time and date are set correctly. I use a radio controlled clock to ensure that my time is accurate to the second. When set follow the instructions to move the tube to alt index (I have tried both moving manually and using the controller with equal success). Once complete rotate the base to point at the meridian (again either manually or using the controls). I then always use the Two star auto align. The controller will present you with a list of starting stars. Choose one that is easy to find (I tend to use Vega). The scope will then slew to approx the location of that star. Follow the instructions to align with the selected star. When complete, you will be given a second list of stars. I normally choose the default one. If a tree is in the way when it gets there, you can choose undo to get back to the selection and choose another one. Again follow the instructions to align on this second star. If all went well you should get Align Success.

4) Next I align the wedge. The Telescope will slew towards Polaris. It may not be exact, but close enough. You are asked to center the scope on the star. Once Complete the scope slews away a degree or so (Polaris is not exactly the celestial north pole). You are now asked to centre Polaris in the scope but not using any of the controller buttons. To move the tube up and down you should use the Wedge. If you are slightly to the left or right adjust the tripod so that polaris is right on the red dot. When everything is lined up in the eye peice, press enter. You are now align exactly with the celestial North Pole. you will find that you now have to carry out a full align again. Follow the steps in instruction 3 again.

Goto
5) Once you have completed the final alignment, you should find that the scope will get fairly close to any target you give it. I tend to do a lot of Astrophotography, for which many of the targets are not easily visible by looking through the scope. To get extremely accurate goto’s, I use the Precise goto function which is accessed through the menu. By using this facility, the telescope will identify a bright star visible to the naked eye and very close to the object you are want to goto. It will slew to the star and ask you to centre on it. (I always follow the track through the red finder scope as it slews to the visible star. This way I can see the star it is heading towards in case it does not end up exactly on it). You will then be asked to centre on this star and press enter. When complete, the telescope will slew to your goto target, making use of the correction information you put in on the star. The Object will be in the centre of your eyepiece.

Accurate Tracking
After you have found your object using goto or precise goto, you need to accurately track it. I make sure it is tracking accurately be immediately using the sync command once goto is complete. This is accessed by using undu until you cant go any further, then pressing the align button. Scroll through the menu options until you get to sync. It may not be necessary to use this command, but I don’t think it can hurt.

I am still perfecting the art of accurately setting up my scope. It still does not track as accurately as I would like, but it is a lot better than it was. Since I tend to take multiple short exposures (between 20 and 60 seconds) I don’t see any real problems with tracking. Last night I set my camera take a series of exposures of the andromeda galaxy. When I got back about 30 minutes or more had elapsed. When I looked through the camera, the Galaxy was still in the centre of view.