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Hi guys and gals

There's been a lot of buying and some modding in the Souith Wales area and I have to admit some of it concerning the flocking of a scope took my interest.

I live in a great position for observation but there is the dreaded light pollution to deal with, AND, I have a Heritage 130P which has an 'open structure'

Anyway the original scope looks like this

post-14434-0-95054300-1340662132_thumb.j

I removed the primary mirror and flocked the main tube.

With the advantage of having the scope in this state I played with the idea of constructing a black card tube, which would slide into the main tube as the scope was closed down and of course would extend as the scope was opened, it too could be flocked and thereby give me a compact scope that would travel with me and give me a fully flock lined tube too

post-14434-0-15724300-1340662551_thumb.j

These pics just ilustrate the other positions showing the tube extending etc.

I also added a couple of layers of flocking to the end of the new tube extension which remains inside the main tube, this acts as a light trap and may eventually allow its use for solar, but I need to take care with this aspect

In any event it will give me a higher contrast telescope for night observation and help with the light pollution

post-14434-0-57872500-1340663192_thumb.j

Gordon

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Hi guys and gals There's been a lot of buying and some modding in the Souith Wales area and I have to admit some of it concerning the flocking of a scope took my interest. I live in a great position f

It has been asked how the mod was completed, well here goes Prior to removing the primary mirror cell I made a number of reference marks using paper tape and marker pen, to ensure I knew its original

The white stuff round the focusser is ptfe tape that I add to reduce the slack in the helical focusser; needs to be replaced from time to time but its worth it Can't comment on the improved view other

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Wow good job, looks very pro! Would love to mod mine the same but i just don't have the inclination or the confidence to mess with my primary. Have you noticed an improvement? Btw what's that white bit on the focuser? And out of interest what's that ep?

Sent from my GT-I8150 using Tapatalk 2

Edited by wyx
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The white stuff round the focusser is ptfe tape that I add to reduce the slack in the helical focusser; needs to be replaced from time to time but its worth it

Can't comment on the improved view other than to say that I am sure it will reduce lp from the sides, at the moment there are just too many cloud magnets operating

Glad you like it, the flocking bought from FLO was a lot easier to work with than I had expected, the rest was really more Blue Peter!

Gordon

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Hi again

In my initial posting I made a small reference to 'the prospect of solar use after further work'

Can I please stress that this mod in intended for NIGHTIME OBSERVATIONAL USE ONLY

Solar observation is a very specialised area

Edited by Mountain View
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Great mod!

Is it a cardboard tube or a piece of card rolled up and what thickness?How is the card attached and kept in place on the 130P?

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Blackboard paint on the back and edge of the secondary seems like a good idea.

I too would love I know more about the 'cardboard mod'. Thickness and how it attaches to the front assembly would be great to know.

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Great looking mod! Might try to do something like that when I about to mod my little dob. Although my DIY skills are... well... not great.

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Ok, let me try to answer some questions, sorry if get names wrong!

Oily.... The card was purchased some time ago from a craft shop, it's fairly stiff, the measured thickness is 0.5 mm

JamesF... Yes it is a 32mm ep which is adjustable for use with lightweight digital camers, as I'm sure you know its a great starting optic size to initially scan the skies

SplijntUK.. yes you're right blackboard paint to the secondary would have been a good idea and is the normal remedy associated with the process of flocking; sadly I didn't have any blackboard paint and had fixed tube in position before realising my error. However, I re-visited my original idea which was to wrap a length of self amalgamating tape around the edge of the mirror. For those who have not come across Self amalgamating tape, it is a rubber based tape which is non adhesive, you stretch it a bit and close one end onto the other, after a short while it will amalgamate and therefore stay in position

Some have asked how it was done so I will add another post once I've sorted it out

The picture below illustrates the tape arounf the secondary mirror, I've checked it against terrestrial targets and it seems ok and gives a matt black edge.

post-14434-0-00979200-1340714677_thumb.j

Edited by Mountain View
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Yes it is a 32mm ep which is adjustable for use with lightweight digital camers, as I'm sure you know its a great starting optic size to initially scan the skies

Indeed so. If I'm not taking my full eyepiece case out with me that is the one eyepiece that is always guaranteed to be put in my coat pocket.

James

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It has been asked how the mod was completed, well here goes

Prior to removing the primary mirror cell I made a number of reference marks using paper tape and marker pen, to ensure I knew its original position, a few photos were taken too

I removed the primary mirror cell carefully and stored it very carefully; this involves removing four screws and a stud which is located in the dovetail.

It takes care to remove but it will come out by easing it gently at the base.

The process of flocking the tube is well described in the link below which I was given to me by others

http://www.cloudynig...php?item_id=805

For the main tube I used a piece of flocking 50cm x 27cm.

This should take you from inside the plastic top rim to below the primary mirror level; you might like to check the 27cm dimension as I didn't make a note at the time, so this is from memory.

I stripped back a small area of the backing paper and started to flock the tube from the seam, gradually removing backing paper and applying the flocking, I ran my hand up and down the tube as I went to ensure no air bubbles; my experience was that it laid quite easily and any excess length can be laid over the start point.

While the mirror cell is out you have access to the tube and this where the 'messy' bit starts.

I used a piece of black 0.5mm thick card 50cm x 30cm and gradually created a tube of not an exact diameter and used several pieces of cellotape to hold the various temporary positions until 'the best' size was obtained

The primary mirror is 130mm diam. but the tube is around 150mm diam. so there is quite a bit of room to play with.

It is a case of trial and error because you want the new tube to slide relatively easily through the fixed tube.

Once I was happy with the size of the tube I used some Black gaffer tape along the outer seam to stabilise the tube, flocking the inside was as above.

Additionally I ran a couple of 2cm strips of flocking around the outside of the tube end that will remain inside the main fixed tube

This process seemed to greatly improve the stability of the tube.

I cut a hole for the ep and used a 35mm plastic film canister to ensure its alignment with the focusser, if you carefully insert the canister from the inside and through the hole you have made you can align the new tube to the focusser.

Its a bit fiddley but is probably better than trying to cut a hole through the tube when its fixed in place, you may also need to cut a notch around the fixing bolt of the secondary mirror, I did.

Fixing this new tube in place involved the careful removal of the shade for the secondary mirror and securing the new tube with a strong double sided tape along the area previously occupied by the shade, this leaves the rest of the tube circumference to remain flexible and probably assists the tube movement

I've sketched an outline of the mod which I can send to you if you wish; I did intend to include it here, but its too small to be useful

Finally replace the primary mirror cell to its original position, collimation might be necessary but so far I don't think it will be necessary, the Heritage seems to be a very stable scope in this regard.

I have a little concern regarding dew when in use, but at this stage I balance that concern against the advantages of a dark tube, we shall have to see.

Please remember that this mod is for night observations only

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Blackboard paint on the back and edge of the secondary seems like a good idea.

I recently bought one of these scopes, could you tell me why theres a need for blackboard paint on the back of the secondary? Thanks!

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I recently bought one of these scopes, could you tell me why theres a need for blackboard paint on the back of the secondary? Thanks!

This is a common mod for reflectors to cut down on extraneous reflected light going down the tube. As I understand it, the most effective thing to do is to create a shroud to block light getting in between the front and back of the extended tube. Then the next is to flock the tube which stops light which enters from oblique angles at the open end of the tube from reflecting all the way down to the primary. Once that is done, the next is to blacken the edges and back of the secondary with blackboard paint which is: 1) black; and 2) a very poor reflector indeed; meaning even less reflected light comes down the tube to the mirror.

The end result is improved contrast and overall scope performance.

So it's: shroud first; then flock; then blacken secondary mirror edges and back; in order of return on effort.

Astronomy shed has some videos on this type of mod done on a SW Quattro 10" - YouTube is your friend for that.

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Thanks SplintUK, great explanation.

I have since used self amalgamating tape to achieve the same affect, I think B/board paint to the edges is perhaps the favoured option though; have explained this in earlier post

Would really love to give an update to my Mod regarding improvement, but there hasn't been a night-time break in the clouds yet!!

You can fix the scope, butyou have wait for the clouds to go...

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I saw the Moon!

Yes, there was actually a small break in the cloud cover last night and this was my first chance to see the improvement of the mod

It was only possible to view the moon but with a moon filter it was the best I've seen it through the Heritage 130

When the cloud was there, (most of the time) there was the dreaded lp above my horizon of Cefn Mawr; with an lp filter it was possible to see the clear line of horizon without orange glow.

So, all in all very pleased with it and looking forward to more improved contrast viewing as and when the cloud moves on

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Congratulations Gordon, that is a great piece of ingenuity. I can't believe Sky-Watcher didn't think of doing that!

Also, what's flocking material?

Edited by Ganymede12
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