Using Microfocuser on LX200

Rodstar (Rod) · #1 14-02-2005, 08:12 PM

It is a steep learning curve Rumples Riot! I haven't a clue how to use the microfocuser...and what really annoyed me was that it got caught in the scope when it was slewing around and the end of the cord at the focus port end broke off! I am hoping Bintel can help fix it! Before that happened, neither Mike or I could get it to make any difference, regardless of which of the four speeds we set the focuser at. It left us with the manual focuser knob, which I am finding is not great at getting a really sharp image.

I think the delays in alignment were user-error (ie ME!!). I may have (strictly "off the record") aligned to the wrong stars a few times!!!! Obviously I just need to get things right with the two alignment stars, and the rest will fall into place. Oh, and did I mention the Martians??

We started about 9.20pm, and finished about 12.30ish. There was a lot of clouds low on the horizon, and so, for example, Jupiter kept disappearing from view - from sharp focussed object to nothing!

I suspect we will have a much more productive night's imaging next time around.

Any tips, Rumples Riot, on how the microfocuser is meant to work? I locked the manual focuser before trying to use it as per the instructions, varied the speed, and used the up and down buttons near the top of the handset. Nothing seemed to make any difference to the image.

Rodstar

iceman (Mike) · #2 14-02-2005, 08:22 PM

Maybe it was broken before then?

Oh and yeh, finding alignment stars (the right ones) will definitely make a difference in a quicker setup time next time out

Next time, attach the finder straight away mr rod star

Striker (Tony) · #3 14-02-2005, 08:36 PM

Rodstar...can you hear the microfocuser working...its loud.....and if its working you will notice it going in and out of focus within about 10 sec......well mine does..

I just adjust the microfocuser until its approx halfway out giving me room to focus either way......I use the left and right arrows but you can use both up and down aswell.

I have never pulled the cords out......touch wood.

Comet Hunter · #4 14-02-2005, 09:01 PM

Ouch! re: microfocuser problem! You'll hear it when it's moving - even when it's at the end of its run it'll still make a noise (at a different pitch though) All it should take is press 'focus' to put it into focus mode then up+down to change..

Good luck getting it fixed - is it just the end of the cable that was stuffed from the slewing? If so just a matter of re-crimping a new connector on hopefully.

Back when I first got my LX200 it took me a few nights to get the star-align to work first time accurately. Give it a few months and you'll be placing the base right over the centre bolt with the first attempt (I'm still trying to master the night time centreing

)

[1ponders] (Paul) · #5 14-02-2005, 09:05 PM

Rodstar, you don't actually need to lock the mirror when you use the microfocuser. The mirror lock helps if you have to focus on a star some distance away from your imaging object and then slew to the object. It stops mirror movement during the slew process. Also for when you cross the meridian when wedge mounted for the same reason. For viewing I don't worry about it. In fact I used to forget that I had it on when viewing the then when I went to adjust focus manually it was still locked. Not recomended.

I have real problems with the cord situation on the meade. Do you uses a 12V powercord. And if so does it get tangled too? And yes the microfocuser cord and Autostar cord, I find, can be a real pain in the butt. Especially getting tangled up with the power lead. Not sure what you can do about the microfocuser cord apart from keep an eye on it when slewing as I do.

Strikers right if your microfocuser is working you will hear it quite clearly. Which arrow buttons were you using? The two at the bottom or the RA and DEC arrows near the top of the hand piece?

rumples riot · #6 14-02-2005, 09:07 PM

Tips. no problem.

First, don't plug the micro focusor in until you have done the alignment.

Second, like Tony said hold the down key or up key and look for the movement. If the assembly does not move then use the other arrow key and it should move. BTW you should only use the up or down arrows not the left right arrows. When the focusor is in the middle of its run and you can tell this because the single thumb screw moves out from its housing. When it is in the centre it will be about three mm from the focusor housing. This is explained real well in the manual.

As for alignment stars go for Sirius and archenar, both of which can be selected during auto alignment by using the arrow keys at the bottom of the handbox. Be advised though that you can only go up and down the list a limited amount. However, you should be able to find a star or two. Also take a star chart out with you to find the alignment stars.

Other than that I can't think at present what else you need to know.

[1ponders] (Paul) · #7 14-02-2005, 09:08 PM

Sorry I should have read your post a bit more carefully about the microfocuser. It sounds like you're using the right buttons. How do you set the speed for your focuser?

Comet Hunter · #8 14-02-2005, 09:19 PM

Quote:

Originally posted by rumples riot
.....

First, don't plug the micro focusor in until you have done the alignment....

Any reason for this RR? I prefer to have everything plugged in before applying power to prevent 'hot plugging' or is this not an issue with the focuser?

Striker (Tony) · #9 14-02-2005, 09:28 PM

Quote:

As for alignment stars go for Sirius and archenar

I also align on these 2 stars......and found once aligned to be very accurate.....all this only takes a few minutes and then your ready to enjoy...good luck...

one thing...I cant remember who told me but someone recommended to slow the slew rate to 4x......I think this will look after your gears a bit better....I have....

What everyone else's thoughts on this rate.

rumples riot · #10 14-02-2005, 09:28 PM

Reason for not plugging in is that you can rip the end off the cord!!!! Hot plugging is not a problem, all plugs except the hand box can be hot plugged. You will find that once the alignment has occurred the scope will only travel to and from one set point. It will not go round and round. So the cord will stretch the right amount and should a star be around the other side from a previous one the scope will simply reverse and the cord will once again go slack. Hope that makes sense.

[1ponders] (Paul) · #11 14-02-2005, 09:38 PM

I think Tony its reduce from 8 degrees per sec to 3 degrees per sec. This quietens the noise and puts less stress on the gears. But its a three times (nearly) slower. If we reduced to 4X sidereal I'd have to get up the next morning to check the first alignment

Comet Hunter · #12 14-02-2005, 09:40 PM

Fair enough, luckily mines never gone to that extreme that it would rip a cord out of its socket while aligning.

As for reducing max slew rate, I cant remember what I put mine down to (think it was no. 4 on the pad) but yeah, apart from reducing extra wear on the gears it also lowers the noise a little.

Rodstar (Rod) · #13 14-02-2005, 10:03 PM

I will:
1. Get the cord fixed
2. Have a play, taking on board the above comments, and
3. Let you all know how I get on

Thanks for the input RR, Paul R and Striker. I'll avoid plugging the focus cord in until after alignment! Good to know that after this the scope won't swing more than 1 revolution.

I use the up and down keys near the top of the handset to try to use the microfocuser. I use the up and down arrows at the bottom to select the speed of the microfocuser.

I have just checked the instructions and can see that I have never set the microfocuser in the halfway position before starting. I will try that next time. I am aware of it making a noise when I press the buttons, maybe it has always been at one end of its limits, and I have just never moved it the other way?! You'll have to forgive me, I'm not at all technologically minded!

Not sure what you mean about "the single thumb screw coming out of its housing" RR - I don't have a thumb screw on my model, and there is no mention of it in the manual. Where on the housing is your thumbscrew???

Rodstar

rumples riot · #14 14-02-2005, 10:34 PM

The microfocusor comes with the internal sleeve set to fully closed. So you will need to move the sleeve out with the down arrow. The thumb screw that I am referring to is the one that you turn to secure the star diagonal into the micro focusor. That will move out depending on what speed you are using. Does that make sense.

Comet Hunter · #15 14-02-2005, 10:38 PM

Your microfocuser doesn't look like this Rod?
http://comethunter.com/images/mf.jpg

When the screw is level with the housing this is aprrox. 1/2 through the run.

rumples riot · #16 14-02-2005, 11:04 PM

Thanks for the shot Andrew, now Rod do you see the thumb screw on the upper right. That screw will move out of the housing of the focusor. It is a good idea to move it all the way out, take note of how far out of the housing it is and then divide that distance and set it to that point. Each time you set up the scope or change the focus with the course focus just simply reset the microfocusor to that point.

That make sense?

BTW, sorry Mike for taking this off track, we need to get back on track and if you guys want we can start a thread on the equipment section to complete. Otherwise we would have railroaded Mikes great shots with an equipment related divergence.

iceman (Mike) · #17 15-02-2005, 06:06 AM

Quote:

As for alignment stars go for Sirius and archenar

THat's what we tried to go for, unfortunately Rod's superkeen eye didn't line the scope up with said stars.. something to do with not having the finderscope attached and aligned

Quote:

BTW, sorry Mike for taking this off track

np, there's been good and relevant information in here, i'll split it off to another thread in the Tips&Techniques forum.

beren · #18 15-02-2005, 09:33 AM

Rod sorry to hear about your problem , hope Bintel can sort it out quickly for you so you can get back out there, i came close to breaking the cord as well when i first used it , the cord got lodged under a arm and nearly squeezed in to the base while revolving . Cant add much because i think everything has been covered but just say make sure you have the tube centred in between the hard stops before undergoing alignment procedures and if you can train and calbrite your drives/sensors . You might find this little mod handy for your coarse focusing ......
http://www.users.bigpond.com/lansma/...ocuser_mod.htm

iceman (Mike) · #19 15-02-2005, 10:16 AM

Great mod, and a nice site he's got there.. I sent him an email

Rodstar (Rod) · #20 15-02-2005, 08:39 PM

Thanks for all of that further info Andrew, Paul and Beren.

I use a 2" star diagonal, so I guess you mean I should be looking at the two thumb screws at the bottom of the photo. It explains why there is the slit in the housing around the screws to allow the movement you are describing. I will look out for this now, and as you suggest Beren, put it half way out before attempting coarse focusing. Makes perfect sense. Just need to get the cord fixed tomorrow at Bintel, and I can give it a go!

I love the look of those mods Beren! I must just play it safe for a while, though, and make sure I am using what I've got properly first!!!!

BTW does anyone know why, beyond the silver Meade cap that you screw off to put the microfocuser on, there is a further attachment on the tube (black), that can also be screwed off? What can be put there, if anything?

Rodstar