Jump to content

sgl_imaging_challenge_2021_annual.thumb.jpg.3fc34f695a81b16210333189a3162ac7.jpg

No planet thru the eyepiece just cross hairs.


Recommended Posts

I just bought a used  Simmons 6450 telescope and per all instructions dialed in the scope but noticed that it did not come with the barlow lens just 3 eye pieces. A 20mm, 6mm, 4mm and a green moon filter.

When we went to locate Jupiter last nite we were able to locate it in the finder scope and eyepiece but it was a white glow with the cross hairs and the suspended mirror against a white sphere through the eyepiece. We used the 20mm. The 4mm and the 6mm were completely dark.
What are we missing? Thanks.

Link to comment
Share on other sites

I am having a hard time understanding what you are seeing in your eyepiece. It's good you are using the 20mm however. Now when you say you see crosshairs, is this through the finder? I ask as I don't understand how crosshairs could be seen in an eyepiece in the telescope itself. And what do you mean by a "suspended mirror?"

Now a few other questions: Did you align the finder-scope during daylight by tuning the scope to focus on a distant object - and then aligning the finder on the same object? If so, then you should simply need to find Jupiter in the finder, and then focus the eyepiece of the main telescope on Jupiter as well. Once you have Jupiter in your 20mm eyepiece, you can fine-tune your finder-scope so both finder and scope are in agreement. Did you get an instruction manual for this scope? If not - here is one. It's Adobe, so if you don't have Adobe Reader - do a search and download/install it. But here's the manual:

http://www.simmonsoptics.com/downloads/manuals/archive/TSI_6450_Telescope%20Assembly%20Instructions.PDF

As for the green moon-filter, that's a new one! It may help, but it didn't come with the scope originally. Moon-Filters are generally gray in colour and cut down light-transmission to 13%. Variable-Polarizing filters are preferable.

So in the last analysis, read the manual and then practice with your scope in the daytime. Get used to focusing and using the mount. Then take a night-time wander.

Clear Skies,

Dave

  • Like 1
Link to comment
Share on other sites

Yup - if you can see the secondary mirror in the view then it's out of focus. As Shane says - wind the focuser all the way in then wind it out gradually and slowly so you don't miss the focus point. As it begins to focus you'll see a big bright circle getting smaller and smaller until eventually it's in focus. If you carry on winding in the same direction it starts to get larger again - so don't wind too quickly.

The secondary mirror will appear to disappear as you reach a small but sharp image. Hth :)

Link to comment
Share on other sites

Dave 

Sorry for the confusion with my terms. What i meant instead of suspended mirror is the secondary mirror, as properly described by brantuk. Also we did printout a manual already and followed the set up directions as best we could. When we aligned the scope we did it the opposite way you prescribed so we will go back and realign. 

as for the green filter it is labeled moon and screws into any of the eyepieces from the bottom.

Moonshine, brantuk

We will slow down in our focusing with the proper aligning.

phoobar

What does the extension do? and would the missing barlow lens achieve that?

Link to comment
Share on other sites

As you get towards sharp focus the planet / star disk gets smaller and smaller. When it's at it's smallest diameter you are at or close to sharpest focus. If the planet / star image is getting larger in the eyepiece you are moving away from the sharp focus point.

  • Like 1
Link to comment
Share on other sites

The scope is a 114/900 so is I guess a spherical mirror but at f/7.9 should be OK.

The 4mm eyepiece will not be any use in real terms, the 6mm may - only may, the 20mm should be the usable.

Meaning you do not have much to play with, suggest you consider a 10mm or 12mm plossl, nothing expensivve - Astronomics do a value line AT plossl at $23. Optcorp have Celestron Omni plossl's at $22. Also you may find a 30mm or 32 mm plossl useful just to find things easier.

Looking at the manual the barlow lens looks LONG makes me think it was a single positive achromatic doublet that would need a long tube, but as you do not have one that is for information only.

  • Like 1
Link to comment
Share on other sites

The scope is a 114/900 so is I guess a spherical mirror but at f/7.9 should be OK.

The 4mm eyepiece will not be any use in real terms, the 6mm may - only may, the 20mm should be the usable.

Meaning you do not have much to play with, suggest you consider a 10mm or 12mm plossl, nothing expensivve - Astronomics do a value line AT plossl at $23. Optcorp have Celestron Omni plossl's at $22. Also you may find a 30mm or 32 mm plossl useful just to find things easier.

Looking at the manual the barlow lens looks LONG makes me think it was a single positive achromatic doublet that would need a long tube, but as you do not have one that is for information only.

Thanks ronin. I'm curious why the small diameter lenses are almost useless. And under what circumstances are they useful? I'll be making the essential eyepiece purchases as finances allow. Would you suggest I also get a proper barlow? 

Link to comment
Share on other sites

Hi rich661 and welcome to SGL. :hello2:

How is the collimation? If you have a local club or society ask/get someone to check it out for you. You should get perfectly formed coincentric circles or doughnuts if it is collimated when de-focussed on a bright star or bright planet.

I am having a hard time understanding what you are seeing in your eyepiece. It's good you are using the 20mm however. Now when you say you see crosshairs, is this through the finder? I ask as I don't understand how crosshairs could be seen in an eyepiece in the telescope itself. And what do you mean by a "suspended mirror?"

Now a few other questions: Did you align the finder-scope during daylight by tuning the scope to focus on a distant object - and then aligning the finder on the same object? If so, then you should simply need to find Jupiter in the finder, and then focus the eyepiece of the main telescope on Jupiter as well. Once you have Jupiter in your 20mm eyepiece, you can fine-tune your finder-scope so both finder and scope are in agreement. Did you get an instruction manual for this scope? If not - here is one. It's Adobe, so if you don't have Adobe Reader - do a search and download/install it. But here's the manual:

http://www.simmonsoptics.com/downloads/manuals/archive/TSI_6450_Telescope%20Assembly%20Instructions.PDF

As for the green moon-filter, that's a new one! It may help, but it didn't come with the scope originally. Moon-Filters are generally gray in colour and cut down light-transmission to 13%. Variable-Polarizing filters are preferable.

So in the last analysis, read the manual and then practice with your scope in the daytime. Get used to focusing and using the mount. Then take a night-time wander.

Clear Skies,

Dave

I used to own a Prinz Astral 500, (refractor), during the early 1980's to early 1990's and that included a green Moon filter. It must have been all the rage back then...

...and you should not worry about not having the Barlow lens. Used with the 2mm & 4mm eyepieces, you are going to have very small and tight eye-relief and I doubt you would be able to focus on anything. I think the finderscope eyepice was 0.925"too, (which I think was a 6x20 with crosshairs), as it would fit into the focus tube and the other accessories that were supplied with it. :icon_salut: 

  • Like 1
Link to comment
Share on other sites

Because certain telescope sellers use the totally erroneous method of 'max magnification' as a selling point.

Barlow NO, there is not point in trying to extend the apparent magnification/change the focal length of your rig until you can clearly see something.

  • Like 1
Link to comment
Share on other sites

Hi rich661 and welcome to SGL. :hello2:

How is the collimation? If you have a local club or society ask/get someone to check it out for you. You should get perfectly formed coincentric circles or doughnuts if it is collimated when de-focussed on a bright star or bright planet.

I used to own a Prinz Astral 500, (refractor), during the early 1980's to early 1990's and that included a green Moon filter. It must have been all the rage back then...

...and you should not worry about not having the Barlow lens. Used with the 2mm & 4mm eyepieces, you are going to have very small and tight eye-relief and I doubt you would be able to focus on anything. I think the finderscope eyepice was 0.925"too, (which I think was a 6x20 with crosshairs), as it would fit into the focus tube and the other accessories that were supplied with it.

I have no idea how to collimate or what collimation is but I'll look it up and get back asap. 

Link to comment
Share on other sites

I have no idea how to collimate or what collimation is but I'll look it up and get back asap. 

I would not worry about collimating the scope just yet. The issue you describe in your first post is caused by the scope being out of focus so that needs some practice. Once you are getting in focus images of your target objects we can think about checking the collimation, which may need some adjustment to fine tune what you see but then again may not.

  • Like 2
Link to comment
Share on other sites

Thanks ronin. I'm curious why the small diameter lenses are almost useless. And under what circumstances are they useful? I'll be making the essential eyepiece purchases as finances allow. Would you suggest I also get a proper barlow? 

rich  the smaller eyepieces are not useless. You may be able to use them on very clear days when seeing is very good, try observing the moon with them first.

You should stick with the 20mm until you resolve your focus issue. worry about the other eyepieces after.

  • Like 1
Link to comment
Share on other sites

One thing I find very irritating with the small eyepieces is that they highlight any "floaters" you may have in your eyes. I bought a 4mm, and can't use it. In fact, I nearly sent it back as faulty, til I realised that the blobs stayed still while I rotated the eyepiece!

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.