Explore Scientific Coma Corrector from US

[Bart]

The ES cc is on sale in the US for $187 which is amazing really. Couldn't help myself at the price with just $37 postage to Ireland on top. Hope Mr Customs doesn't spot it......but even if he does, it still a bargain!

[Oortrageous]

Congratulations and enjoy! If the skies where you are are in the same league as Moycullen I'd say it'll be put to good use!!

[Louis D]

The other way around, there is no customs on items costing less than $200 coming into the US.

[Don Pensack]

One note:

You will need 32-35mm of additional in-travel on your focuser to use the ES HRCC.

You might need to move the primary mirror up a bit to accomplish it.

Start with your in-most travel eyepiece, insert it in the HRCC (top rolled down) and focus the scope.  Look at the edge.  Star image not round?

Move the top up a couple millimeters and refocus the scope.  Edge better?  Keep going until you find the setting that corrects the eyepiece completely at the edge.

Then, lock the focuser (metaphorically) and, for every other eyepiece you insert, focus the eyepiece with the top of the HRCC.

Look at the settings on the side and write them down--you can pre-dial the settings before you insert the eyepiece the next time.

If you've got each eyepiece focused, your total focuser travel in the future might be a millimeter or so because the movement of the top essentially parfocalizes your eyepieces.

Now, if it turns out that you need a LOT of travel of the top between the in-most and out most eyepiece, that could be a pain in the field.

What you do then is to use parfocalizing rings or o-rings, or spacers to parfocalize all your eyepieces with the in-travel most eyepiece you own WITHOUT the HRCC

And then, all the eyepieces will use the same setting of the top of the HRCC after that.

By optimizing the edge of the first eyepiece, you are setting the HRCC in the light cone from the primary, and that's where it should stay.  Moving the top in and out

is merely adjusting the focal plane of each eyepiece to be the same distance from the HRCC lens.

Hope that helps.

[Bart]

Din

many thanks for that. Seriously hope I don't require moving the primary, sounds a bit scary. 

Thanks again for help.

regards

barry 

[Bart]

Well, it arrived today 'sans duty', hooray! That's €200 new, excellent   

Now to check if I need to mess with the primary to get the infocus mentioned previously by Don above (thanks again for the heads up) when I get a chance to put it in under clear skies. 

I'd also like to ask a possibly stupid question. If I use this in different scopes, I imagine all the settings for particular EPs will be different in the next scope. They're f5 and f4.5 as I imagine this is important  

The really great thing is, I'm officially finished spending on Astro gear!.............?!?!?!?

[Bart]

Well, a quick update. I do need additional infocus unfortunately. 

I understand I need to move my primary up the tube. I was looking for longer primary Collimation bolts. However, I found that the Farpoint Collimation bolt can be removed from the knurled handle. I was able to replace them with longer M8 threaded bolt. This should enable me to push the primary forward another 15mm, once I add some spacer to put between the mirror cell and the base to allow the Collimation Spring to take the tension. Pictures of the original bolt with the adjusted longer ones. Easier than I originally imagined. Hope it works. 

[Bart]

Update: installed and ready to set up

[spaceboy]

Please do not take this the wrong way as it is to some a stupid question but one that has caugh some astronomers out. You are putting the cc directly in to the focuser and not into the 2" adapter as I have seen this done. I am also aware that some 3rd party focusers will not allow the cc to fit all the way down the draw tube. This tends to be ones that have minor baffeling with in the focuser tube itself like Revelation and GSO DS focusers.

Glad to hear it made it through customs but be aware that some couriers like DHL send you a bill at a later date for any handling and custom charges. 

[Louis D]

2 hours ago, spaceboy said:

Glad to hear it made it through customs but be aware that some couriers like DHL send you a bill at a later date for any handling and custom charges. 

I don't know about UK customs, but for things shipped to the US, there's no customs/duty/tariff on items under $200.

[spaceboy]

1 hour ago, Louis D said:

I don't know about UK customs, but for things shipped to the US, there's no customs/duty/tariff on items under $200.

The UK and (I assume all of) Ireland it's under £35 and even then it has to be marked as gift. Depending on what the contents are there is still a chance you have to pay something.

[Don Pensack]

On 5/4/2016 at 14:12, Bart said:

Well, it arrived today 'sans duty', hooray! That's €200 new, excellent   

Now to check if I need to mess with the primary to get the infocus mentioned previously by Don above (thanks again for the heads up) when I get a chance to put it in under clear skies. 

I'd also like to ask a possibly stupid question. If I use this in different scopes, I imagine all the settings for particular EPs will be different in the next scope. They're f5 and f4.5 as I imagine this is important  

The really great thing is, I'm officially finished spending on Astro gear!.............?!?!?!?

No, the setting determined in one scope for a particular item will be used in another scope as well.

When you correctly set the distance for an eyepiece, what you have essentially done is to set the coma corrector in the right place in the telescope's light cone.

And determined how the focal plane of the eyepiece is set back from the CC lens.

If you use that same CC position for the eyepiece in a second scope and focus, you automatically position the CC correctly in the second scope's light cone.

[Bart]

Thanks for that Don. Darkness has arrived again in my part of the world, so I'll be setting it all up very soon.