Hotec advanced laser collimator

[pyrasanth]

I purchased the Hotec advanced laser collimator from FLO this weekend. It's a superb piece of equipment but as always it has a learning curve which at times can be frustrating but it becomes strangely easier to use when you have successfully collimated your telescope once with it. This device works great with all optical systems even the Celestron edge HD which I had problems using a normal collimator with.

Watch the videos on the FLO site loads of times to become familiar with the collimator. The video makes the task of collimation look easy. I can assure you it is not as easy as it looks but with practice I'm sure the task will become a lot faster. I spent  good few hours initially & the first day gave up in tired frustration- mostly due to collimated on an equatorial mount in a confined space- not good for the sanity.

I wrote a few notes below which will help anybody get the best from the collimator. This worked for me.

Quick guide to using the Hotec advanced collimator for Sanity protection.

What really helps when using the advanced laser collimator. These instructions are for a Celestron Edge.

A clear area so you can walk around the tripod & the OTA without bumping into either

A very sturdy tripod with adjustable center column (even better if on an adjustable crank)

If you have a German Equatorial mount remove the OTA & place flat on a table with the corrector pointing toward the collimator

(It's a pain to work with the OTA mounted high- despite how easy it looks on the videos). Most kitchen tables are pretty much level and I collimated my telescope in the kitchen on the dining room table & a concrete floor helps for stability.

Mount the supplied tilt adjuster and collimator on the tripod & use a spirit level to get the top of the collimator level.

Turn the collimator to mode one only and get the cross pretty much centered in the secondary mirror. This is not your final setting but will help you considerably get the height of the tripod correct relative to the lasers. The idea is to get a small neat cross pattern initially anywhere on the screen then move the cross to the center by adjusting the tripod in height and lateral movement of the tripod left or right.

Make the insides of the horizontal cross hairs touch the zone between ring 1 & 2. If you can't do this then quite simply your orientation is wrong between the tripod & tube. By carefully moving the tripod & the OTA left or right on the table it is possible to get this position. Don't despair it takes a little time but you will get there. Use the adjusters on the supplied stage to keep homing in on the final position. You require all the outer edges of the laser lines to just touch zone 4 on the grid. All of the lines must touch so if you connected the lines you would form a square.

When your happy this is as close as you can get with the alignment remove the secondary mirror (on a fastar system) place the mirror accessory in the eyepiece holder & if the alignment is successful the laser should be nearly dead center in the mirror grid. If the grid is way off dead center then the eyepiece holder is not concentric to the optical axis (which is very unlikely). If you do a very careful inspcection of the laser grid on the collimator you will see that minute changes can quickly make massive differences to the position of the laser on the mirror reticle. BY adjusting carefully the collimator you should be able to correct the position of the dot. DON'T MOVE THE OTA TO CENTER THE DOT only the collimator!

When your happy with the above step you can move on to the fun bit. Replace the secondary mirror and keep the mirror in the eyepiece holder. Change to mode 2 on the collimator and if your lucky you should see 3 dots. If you don't see 3 dots then you need to pull focus in & out so the dots merge into the center of the reticle. If you don't see the dots its either because the OTA has not been correctly squared to the OTA or you have not selected mode 2 on the collimator. When the 3 dots have merged on the mirror grid you should see on the collimator screen three blobs with concentric rings at 120 degrees apart. These represent the secondary mirror mirror and the collimation screws. Adjust the actual secondary mirror screws to pull the merged dot into the center mirror and make sure that the red blobs on the collimator all sit on the same ring in the same relative position. There may be a subtle difference to what you see as centered in the eyepiece mirror and centered on the collimator grid. This is all down to your initial attention to detail on the initial collimator OTA alignment. The rule for adjusting collimator screws is to always tighten & never loosen more than 2 screws at once. It is easy once you practice. Bobs knobs make this easier but better to change screws before you collimate!

Congratulations- your telescope should be collimated. It is strange that you can spend hours doing this the first time-go away & rethink & then it takes an hour...then 15 minutes. Enjoy!