Help with Meade LX85 Maksitov Cassegrain 6"

[Pthreat]

Hello guys how are you doing.? Im a total beginner with astronomy, but since 30 something years Ive wanted to have a telescope.

 As I wanted a telescope which would be ideal for beginners but would allow me to get more into an intermmediate level I bought a Meade LX85 6" Maksutov Cassegrain. Im also planning in getting into astrophotography but this will be something I will do after I get the basics right.

Today during the early morning I took the telescope out to do moon gazing, I was able to at least point the tracker to the moon and was very pleased with what I saw, however using the 26mm super plözl multicoated eye piece was dissapointing to say the least.

I figured out by my own that I should probably align the tracker during day time with the main tube. So I pointed the main tube to an object far in the distance and then proceeded to align the tracker right on the X spot. I did the alignment by just using the diagonal mirror eye piece since it proved to be simple enough.

During this time I was able to observe a black dot during calibration in the middle of the tube and I was a little concerned. 

I did some research during the afternoon and read in some forums that this black dot in the middle could be related tonthe secondary mirror.

I calmed down and proceeded to go outside and use my telescope  which was left outside several hours, i had coverrd the main tube with the lids and a I threw in a light jacket over it to keep it out of sight from prying eyes (where I live in Argentina having a telescope is not something common).

About 19:05 PM venus was north west so I gave it a shot and pointed the tracker at it. I took a look with the 26mm eye piece however I could only see a difuse blob of what I thought it was venus. This blob was perfectly round, there was no black spot in the middle while using the 26mm eyepiece.

I then proceeded to point at antares with the tracker and then took a look again with the 26mm and I saw nothing.

I did some more research and read that this problem could be due to need for collimation on my main scope.

As you can tell I have handled the telescooe manually without using the GoTO system, the scope didnt come with a regular adapter but with a cigarette lighter adapter, I do have this solved and the 12V 5Amp adapter will arrive tomorrow.

 Attached I have left some pics from the main scope which I have taken while using the diagonal mirror indoors with my phone (my phone has several cameras so pics might look strange).

Questions are basically:

Is the black do the secondary mirror or should I collimate the main scope?

why I wasnt able to see venus crystal clear witj the 26mm eye piece? 

 

Thank you very much for reading thisfar, if you have any questions please let me know and I will reply ASAP.

 

 

[Cornelius Varley]

6 hours ago, Pthreat said:

Is the black do the secondary mirror or should I collimate the main scope?

why I wasnt able to see venus crystal clear witj the 26mm eye piece? 

Hello and welcome to SGL. From the description it appears to be that the telescopes wasn't focussed correctly. When the telescope is focussed correctly the black dot should disappear.

[dweller25]

Hello @Pthreat and welcome to SGL.

The black dot you can sometimes see is due to the secondary obstruction and is normal.

You will always need to readjust focus whilst viewing different targets.

Venus is very low so you will get a lot of atmospheric disturbance.

Make sure you are not observing on hot concrete or near hot rooftops - the thermals will lead to very poor images in your scope.

The best way to align the finder is to find a star in the telescope first at around 45’ high and then adjust the finder to put it centrally on the crosshairs.

Make sure the scope is well collimated.

[RT65CB-SWL]

Hi @Pthreat and welcome to SGL. 

Focussing Maksutov's and SCT's does take a lot turns of the focus knob/wheel before it is sharp. As @Cornelius Varley and @dweller25 mentioned, the 'black dot' is the secondary obstruction.

Some eyepieces also do this too when your observing eye is not directly centred over it. It used to happen to me with my Meade ETX105 and a TeleVue 6mm Radian when I did not use the supplied pupil guide. (images and instructions below).

      

TV Radian Eyepiece Instructions.pdfTV Pupil Guide Instructions.pdf

 

Below is an image of what Jupiter looked like through my Meade ETX105 with poor collimation.

 

 

Edited July 3, 2021 by Philip R

[Pthreat]

5 hours ago, Cornelius Varley said:

Hello and welcome to SGL. From the description it appears to be that the telescopes wasn't focussed correctly. When the telescope is focussed correctly the black dot should disappear.

Even with the diagonal mirror only? So should I spin that focus knob until the black dot goes away?

[RT65CB-SWL]

9 minutes ago, Pthreat said:

Even with the diagonal mirror only? So should I spin that focus knob until the black dot goes away?

Yes!

[Cornelius Varley]

12 minutes ago, Pthreat said:

Even with the diagonal mirror only? So should I spin that focus knob until the black dot goes away?

If you look through the diagonal, without an eyepiece, you will see the reflection of the secondary mirror surrounded by the baffle tube. if the telescope is out of focus, with an eyepiece attached, you will see a series of concentric rings. These will become smaller and disappear when the telescope reaches focus.

[Gonariu]

Hi Pthreat, welcome to the forum and congratulations on the nice telescope, a 6 ”Maksutov is phenomenal for Moon, Sun, planets and double stars! For Venus, keep in mind that, in addition to being low (and therefore I agree with the observations already made for the turbulence of the air), having recently emerged from the upper conjunction, its phase is certainly almost that of the full Moon and in addition you have a disk very small about 10 "; in what you said about how you saw Venus I find myself there!

[RT65CB-SWL]

I forgot to mention in my earlier reply that my image of Jupiter was when it had the ABS plastic flip-mirror housing and not the aluminium backplate as shown.

The aluminium backplate came along a few months later after it fell off the mount I was using at the time and damaged two of the three mounting points.
I persuaded a local engineering workshop to make it for me as I could not obtain a replacement via Meade or dealer/reseller. 

Edited July 3, 2021 by Philip R

[Pthreat]

4 hours ago, Gonariu said:

Hi Pthreat, welcome to the forum and congratulations on the nice telescope, a 6 ”Maksutov is phenomenal for Moon, Sun, planets and double stars! For Venus, keep in mind that, in addition to being low (and therefore I agree with the observations already made for the turbulence of the air), having recently emerged from the upper conjunction, its phase is certainly almost that of the full Moon and in addition you have a disk very small about 10 "; in what you said about how you saw Venus I find myself there!

Thank you for your reply 😀

Is turbulence also that bad during winter? Im having 8 celsius to 6 celsius at 19:00 pm. Could you explain me or point to an article in which I can understand whats the ideal weather for observing?

[Gonariu]

Hi Pthreat, you have to observe these points:
1) an object must be at least 30 ° high above the horizon, this is not always possible and then it becomes a virtue of necessity by possibly observing the meridian. For example, where I live (Orotelli in Sardinia) I am at a latitude of about 40 ° N, so the Sun is at local noon at about 26 ° above the horizon. In the morning I am at school and come home at 14 - 14.30, so when I observe it in the early afternoon it is even lower: it adapts to it;
2) if there is too much wind or the stars sparkle too much it is not a night for high resolution observations so either you use lower magnifications or forget it, I personally forget it;
3) in summer the air is calmer, in winter it is more agitated, it is not a question of temperature (at least I think);
4) small diameters are less subject to air turbulence, a system would also diaphragm the instrument as Lowell did by observing Mars with his 60 cm refractor which was often diaphragm at 38 cm; for a Maksutov I would not know how to do as it would increase the obstruction with a central diaphragm, here I leave the word to someone else in the forum.
Take care, good observations and clear skies!

[Tiny Clanger]

I don't think anyone has mentioned the need to let the telescope adjust to the ambient temperature yet ? We generally think of this as 'cooling' in the UK , but OP does not mention where they are, so who knows, it could be warming from aircon that's required ...

My mak needs at least 20 minutes , ideally more, to equalise its temperature with the night air, and not have internal air currents make the view poor.

Low angle of view means you are looking through a greater thickness of atmosphere, which obviously impacts the view, as does any cloud.

 

Plenty of information out there on the subject of weather, transparency and seeing, e.g.

https://skyandtelescope.org/astronomy-equipment/beating-the-seeing/

https://www.accuweather.com/en/space-news/the-best-weather-for-stargazing/693840

https://www.handprint.com/ASTRO/seeing3.html#evaluation

[Pthreat]

On 03/07/2021 at 18:54, Tiny Clanger said:

I don't think anyone has mentioned the need to let the telescope adjust to the ambient temperature yet ? We generally think of this as 'cooling' in the UK , but OP does not mention where they are, so who knows, it could be warming from aircon that's required ...

My mak needs at least 20 minutes , ideally more, to equalise its temperature with the night air, and not have internal air currents make the view poor.

Low angle of view means you are looking through a greater thickness of atmosphere, which obviously impacts the view, as does any cloud.

 

Plenty of information out there on the subject of weather, transparency and seeing, e.g.

https://skyandtelescope.org/astronomy-equipment/beating-the-seeing/

https://www.accuweather.com/en/space-news/the-best-weather-for-stargazing/693840

https://www.handprint.com/ASTRO/seeing3.html#evaluation

I did but I guess it was lost in the text, Im in Buenos Aires Capital Federal Argentina near Caballito thanks for the links!

[Pthreat]

Well as someone said above. It was only a matter of reaaaaally turning that knob !!!! This is Venus which was really low but the cool guys Jupiter and Saturn come out waaay to early for me and I have to work 😀

I have a 9mm and a 26mm eye piece this picture I took it with the 9mm eye piece. Which eye pieces could I get that would be great for planet watching?

Thanks!

[Pthreat]

1 minute ago, Pthreat said:

Well as someone said above. It was only a matter of reaaaaally turning that knob !!!! This is Venus which was really low but the cool guys Jupiter and Saturn come out waaay to early for me and I have to work 😀

I have a 9mm and a 26mm eye piece this picture I took it with the 9mm eye piece. Which eye pieces could I get that would be great for planet watching?

Thanks!

Yes its a crappy pic I took with my phone sorry for the quality I still havent set my cannon rebel, waiting for that when control cables arrive

[Pthreat]

Ps: I left the telescope outside for about 3 hours before proceeding to any observation 😀

[Pthreat]

On 03/07/2021 at 09:45, Philip R said:

Hi @Pthreat and welcome to SGL. 

Focussing Maksutov's and SCT's does take a lot turns of the focus knob/wheel before it is sharp. As @Cornelius Varley and @dweller25 mentioned, the 'black dot' is the secondary obstruction.

Some eyepieces also do this too when your observing eye is not directly centred over it. It used to happen to me with my Meade ETX105 and a TeleVue 6mm Radian when I did not use the supplied pupil guide. (images and instructions below).

      

TV Radian Eyepiece Instructions.pdf 938.47 kB · 55 downloads TV Pupil Guide Instructions.pdf 419.23 kB · 27 downloads

 

Below is an image of what Jupiter looked like through my Meade ETX105 with poor collimation.

 

 

It was like you said, I reaaaaaally had to turn that knob! See potato pic of Venus above