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Skywatcher 200p daft question

muttley

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muttley

muttley

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My new Skywatcher 200p dobsonian arrived today! I was rather taken aback by how large it was in the flesh, but had great fun building it with my 8 year old. The sky was beautifully clear all afternoon, but naturally it clouded over as soon as the scope was ready. Typical!

My daft beginner's question is as follows: the primary mirror seems dangerously exposed underneath - it looks like it could easily get kicked or knocked if you were a clumsy lump. Shouldn't it have some sort of protective cover over the bottom of the tube as well as the top?

Simon

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twotter

twotter

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My 200P dob doesn't have a cover for the primary mirror at the bottom end of the tube either. I've never had a problem with it, and I think it helps cooling, as well as being more convenient when collimating.

Happy new telescope :D

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muttley

muttley

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? eh ?? is it a flex tube or regular scope ?? its a tube with a mirror at the bottom .....

what do you mean by protective cover at the top ??? :D

It is a regular scope. My question referred to the lack of protection for the underneath of the mirror. Judging from other owners, this seems to be normal. I will just have to be careful!

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jimmyjamjoejoe

jimmyjamjoejoe

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It's normal, the non-dob version comes with a plate though. I keep a wooly hat over mine (branded "animal" for added cool) to keep out dust etc.

I have recently build a fan housing for mine out of a builders bucket, which i cut the bottom off and left enough of a lip to slot over the end of the scope by an inch or so. I then cut a hole big enough for the fan and attached it via sticky velcro to the outside (not enough room to go inside and sit flush). I wired the fan to a usb cable, which is poked through a small hole, and i bought an "emergency charger" from ebay for £2 - It's basically a usb slot powered by 2 x AA batteries, and lasts about 7 hours on my 80mm fan.

Either way, my primary is covered when in storage or in use.

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yonner

yonner

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My new Skywatcher 200p dobsonian arrived today! I was rather taken aback by how large it was in the flesh, but had great fun building it with my 8 year old. The sky was beautifully clear all afternoon, but naturally it clouded over as soon as the scope was ready. Typical!

My daft beginner's question is as follows: the primary mirror seems dangerously exposed underneath - it looks like it could easily get kicked or knocked if you were a clumsy lump. Shouldn't it have some sort of protective cover over the bottom of the tube as well as the top?

Simon

I just bought one to.The salesman suggested a shower cap for the open end to keep the bugs out (it is kept in the shed).I presume this should be removed during use to aid cooling otherwise they would have a permanent cap of some sort?

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stevetynant

stevetynant

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I just bought one to.The salesman suggested a shower cap for the open end to keep the bugs out (it is kept in the shed).I presume this should be removed during use to aid cooling otherwise they would have a permanent cap of some sort?

I'm not sure what you mean by this - the open end is where the smaller / secondary is as far as I know and there was a plastic removeable tube cover for this which you should have. Where the primary is at the bottom of the scope it is completely sealed any way so not sure how anything could get in there anyway?

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Tribal-Wolf

Tribal-Wolf

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My scope has no bottom cover, it has a plastic cover for top of the bottom half of the tube and an elasticated 'shower cap' type cover for top of the top half. Being a flextube I wondered if there was supposed to be a cover for the bottom of the top half?

Did that make any sense?

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yonner

yonner

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I'm not sure what you mean by this - the open end is where the smaller / secondary is as far as I know and there was a plastic removeable tube cover for this which you should have. Where the primary is at the bottom of the scope it is completely sealed any way so not sure how anything could get in there anyway?

Just had a look at the primary end,it's hard for me to say if it is sealed as there is a gap between the very end and what looks like a plate. If someone can verify that it is in fact sealed I will not bother with the shower cap.

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jimmyjamjoejoe

jimmyjamjoejoe

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My scope has no bottom cover, it has a plastic cover for top of the bottom half of the tube and an elasticated 'shower cap' type cover for top of the top half. Being a flextube I wondered if there was supposed to be a cover for the bottom of the top half?

Did that make any sense?

lol yes it made sense, and no i doubt it needs one once it's collapsed.

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stevetynant

stevetynant

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Just had a look at the primary end,it's hard for me to say if it is sealed as there is a gap between the very end and what looks like a plate. If someone can verify that it is in fact sealed I will not bother with the shower cap.

just checked mine again - no your right it is not completely sealed of course- so perhaps if your keeping it in a shed a shower cap might be a good idea to stop the spiders building nests in there.:D

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yonner

yonner

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just checked mine again - no your right it is not completely sealed of course- so perhaps if your keeping it in a shed a shower cap might be a good idea to stop the spiders building nests in there.:D

Is there a reason for it not to be sealed?

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Caelus

Caelus

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I can see why you think there was a cover missing - I built mine yesterday and had the very same thought when I was looking at Astro Baby's collimating guide which shows and instructs the removal of the cover.

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jimmyjamjoejoe

jimmyjamjoejoe

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It's to aid cooling, and no it isn't sealed. With no cap there, air can circulate around the mirror much more freely. What you see at the back there is actually the back of the mirror, just a big chunk of frosted glass.

Having it open isn't really any danger unless you go rolling it around in a dog bed or other dusty places, or unless to have a habit of kicking the scope from below (in which case, perhaps you should observe in just your socks)... Just be sure to cover it if you store it somewhere extremely dusty or "buggy".

Or you could just knock up a hard cover for it by cutting the bottom off a bucket.

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spaceboy

spaceboy

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The older Helios / Blue tube SW's came with a primary cover. You had to undo 3 tiny PH1 screws (trying not to loose them) and remove the cover to access 2mm allen primary locking screws and PH2 collimation screws. Imaging having to do that in a pitch black field in the middle of no where with a red torch as your only form of light. Newer Black livery SW reflectors come with primary collimation/ locking thumb screws and do away with fumbling around in the dark with tiny screws, allen keys and screwdrivers. The collimation screws were also upgraded to a spring retainer as apposed to a rubber "O" ring on the older models reducing the risk of pinching the optics and helping hold collimation better. I also assume with no cover in place air can circulate the mirror better and cool the scope down quicker meaning more observing time but as you say at the risking an exposed mirror. Either that or Synta were sick of people ringing for replacement screws for the primary cover :D In all fairness though scopes are optical instruments and even with a cover on they can be damaged through mishaps or less than careful use. I have heard of more primaries being damaged by people dropping some thing on the mirror while adjusting the secondary than catching the rear of the mirror.

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twotter

twotter

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Just deviating slightly.

Have any of you mounted your 200P on an equatorial mount? I am considering buying an NEQ6 mount for astro photography.

Any thoughts?

I've certainly thought about it, but I was think of a CG5-GT, HEQ5 Pro or the incoming Meade LX80 for visual use only.

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jimmyjamjoejoe

jimmyjamjoejoe

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Just deviating slightly.

Have any of you mounted your 200P on an equatorial mount? I am considering buying an NEQ6 mount for astro photography.

Any thoughts?

Sent from my GT-I9100 using Tapatalk

Max weight for that mount is 25kg apparently, the OTA is about 10kg. They say you should be around half of the max weight for the mount to ensure smooth guiding, so you'd be pushing it once you get cameras and guidescopes on there.

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