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Seben's Big Boss 1400mm-150 Reflector

The Sailor

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The Sailor

The Sailor

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Can someone explain to me the use of the numbered rings on the EQ3 mount. The rings on my mount move freely and I cannot see what puropse they achieve. I have used mounts previously but with fixed rings but they were for a different application. Have searched the net but to no avail.

Jim

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The Sailor

The Sailor

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[ATTACH]31157[/ATTACH]

I found this photo on the net, it show two rings, the top ring is above the weight and is numbered 0 to 9 to 0 to 9 back to 0. The bottom ring is numbered 0 to 24. Okay I have just read that thay are setting circles used for "star hopping", still confused by this. I would understand if they were static and could be used to align the telescope to a very rough direction.

Jim

I have found a webpage giiving me an explanation of what they are and am reading that now

I now understand what they are for, have to say that is what I had thought anyway. The problem I still have is why are they loose and should they be static?

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Astro_Baby

Astro_Baby

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The Scale above the weight is the DEC scale. On some mounts this is fixed and will rotate in synch with the DEC movement. Some mounts it will move but will have a small lock screw that locks it into place.

The other one is the RA scale and that will move with the RA axis though I can see in that pic that it definitely has a locking screw as well.

The scales will have an index mark near them on the mount (in the pic I put up you can see the white arrow next to the RA scale) - its normal for the scales to move in synch with the mount.

You can use them for star hopping but usually they are too inaccurate on most mounts unless you REALLY get some wedge out. The ones on my HEQ5 are dreadful and the EQ6 is the same I am told.

The RA scale can also be used in conjunction with a polar scope to get accurate polar alignment for the mount.

Both of these are quite big topics but if you want some pointers just ask and I am sure someone can answer.

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The Sailor

The Sailor

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Astro_Baby, thank you, good explanation. As said I have actually used rings like these but in other applications and they did have locks, which when I read what their application was for was suprised they were loose. I may look at ways in which I can clamp them as I would use them.

Jim

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haitch

haitch

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My father-in-law has exactly the same scope out in Spain. Be warned the Seben EQ3 mount is nothing like the ones you'll find on a Skywatcher, Celestron, etc so don't go looking for motors or goto setups they just aren't there.

As people say the optics on these aren't brilliant as they use a short focal length spherical mirror instead of a parabolic one and implement a lens in the focuser tube to try to correct the image and increase the effective focal length. That said I've had some fairly pleasing views of the moon, planets and a few planetary nebulae through my father-in-law's. This was helped by him living in a rural mountainous area in Spain with no light pollution (my wife commented it was getting cloudy one night but I pointed out to her that was the Milky Way she was looking at). Don't get too disheartened by the cheap and cheerful comments. It is a useable scope and I think they are value for money. I've got a 6" Helios short tube which employs a different system to lengthen the focal length and correct the optics. Helios are now Skywatcher so it is one of the known brands and the Seben doesn't compare too badly along side. What you will probably find is the mount will vibrate a lot largely due to the skinny aluminium tripod legs. There are various ways to stabilise them such as filling them with sand or filler foam to reduce resonance and keep them as short as possible when in use (when I'm out at the in-laws I use his sitting down).

Have fun with it

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The Sailor

The Sailor

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My father-in-law has exactly the same scope out in Spain. Be warned the Seben EQ3 mount is nothing like the ones you'll find on a Skywatcher, Celestron, etc so don't go looking for motors or goto setups they just aren't there.

As people say the optics on these aren't brilliant as they use a short focal length spherical mirror instead of a parabolic one and implement a lens in the focuser tube to try to correct the image and increase the effective focal length. That said I've had some fairly pleasing views of the moon, planets and a few planetary nebulae through my father-in-law's. This was helped by him living in a rural mountainous area in Spain with no light pollution (my wife commented it was getting cloudy one night but I pointed out to her that was the Milky Way she was looking at). Don't get too disheartened by the cheap and cheerful comments. It is a useable scope and I think they are value for money. I've got a 6" Helios short tube which employs a different system to lengthen the focal length and correct the optics. Helios are now Skywatcher so it is one of the known brands and the Seben doesn't compare too badly along side. What you will probably find is the mount will vibrate a lot largely due to the skinny aluminium tripod legs. There are various ways to stabilise them such as filling them with sand or filler foam to reduce resonance and keep them as short as possible when in use (when I'm out at the in-laws I use his sitting down).

Have fun with it

haitch, Yes, agree there, I have it and will use it. My intention is to learn the mechanics of stargazing from it, once I am happy I will look at upgrading. At the moment I have done what you done with the legs, has not been a problem, I will motorise it but in my own way, have already motorised the focuser and attached a camera from the computer, next will be a motor on each axis and with software on the computer hopefully a goto scope :). For me, at the moment, it is a testbed me so am happy.

Jim

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haitch

haitch

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have already motorised the focuser and attached a camera from the computer, next will be a motor on each axis and with software on the computer hopefully a goto scope :). For me, at the moment, it is a testbed me so am happy.

Jim

Glad you are enjoying it. I made a focus motor for my Helios but ended up taking it off when I upgraded the mount to a CG5 with 2" steel legs - just wasn't needed as it was rock steady even at high magnifications.

Don't get too carried away spending money on upgrading that mount - it probably won't handle your next scope as it's already pushing it's limits with a 6". Then again if you are doing DIY, learning as you go, not spending too much money and if you can reuse your homebrew motor set up on your next mount...

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The Sailor

The Sailor

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Ladies and Gents, I am happy to say that I am dumping my Seben and will be looking for a new scope soonest, or before the summer at least :D . I will use the Seben as a test bed for all the gizmos I play with, I have as everyone has pointed out to be a cheap and nasty bit of kit, glad to say I did not spend too much on it and hoipefully can transfer any items over to a new one. So to that end I would like you to recommend to me whatever you think I should buy, in your own time, go on :) .

Jim

PS, And yes, I know you told me so!!! ;) .

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John

John

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Ladies and Gents, I am happy to say that I am dumping my Seben and will be looking for a new scope soonest, or before the summer at least :D . I will use the Seben as a test bed for all the gizmos I play with, I have as everyone has pointed out to be a cheap and nasty bit of kit, glad to say I did not spend too much on it and hoipefully can transfer any items over to a new one. So to that end I would like you to recommend to me whatever you think I should buy, in your own time, go on :) .

Jim

PS, And yes, I know you told me so!!! ;) .

Jim,

Well I'm really glad the experiences with the Seben have not put you off the hobby - I think you have taken a really positive approach to it ;)

Looking forward to kicking around ideas for a replacement on the forum in due course.

Cheers,

John

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The Sailor

The Sailor

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Thanks John, no, have not lost interest, have always been interested and only just now been able to do something about it. As to how much, I am looking at spending about £500, that will be for scope, tripod, goto mechanism, connection for computer and computer software to drive scope. Would be grateful also for pointers to reputable stores.

Jim

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NickH

NickH

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Celestron CG5/SLT setup would fit that budget, give you nice optics (ED80 calibre) good goto, computer connectivity and some freeware like Cartes Du Ciel would handle the reset.

with a sub £500 budget, for a goto setup, new, that would be my choice

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pvaz

pvaz

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That's an excellent budget, taking under consideration you want a good mount with all the electronic features and a scope and you wan't to go into photography later on.

I would suggest this:

Reflectors - Skywatcher Explorer 150P OTA

with the HEQ5 Pro GOTO mount. That will give you a mount with good results for photography that will allow you make changes on the telescopes if you want to. The cost will be £865, which leaves £135 left for bits you'll have to buy to attach a DSLR to it. Putting a 80mm APO refractor on it would actually be better for photography but would compromise too much on observing, I think.

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adamsp123

adamsp123

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How about the CG5 goto from FLO at £499 this is a very good sturdy mount, the only downside is that at full slew rate in goto mode it is NOISY, at slower speeds when run manually it is quiet so some slew in maual to near the object and use the goto for the final last bit, you can also use is for imaging as well with a suitable scope say a 200mm Skywatcher Newtonian.

Or look for some secondhand kit.

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