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monolith
newbie
Reged: 09/01/07
Posts: 2
Loc: Warrington, UK
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Hi,
Any reassurance the folks here can offer after the following 'incident' would be most welcome.
My first attempt at afocal imaging with a compact digital camera (Nikon Coolpix 4500 directly coupled to a 32mm eyepiece) on the 4SE quickly came to an end as soon as I tried to manually slew the scope in altitude: with a smell of burning and the whine of a struggling motor.
Luckily this occured 2 weeks before the warranty expired - a quick call to the UK supplier confirmed this 'should not have happened' with such a relatively light load and that they had the spare parts in house to effect a quick repair.
Now the 4SE Mak is supposedly designed as a telephoto lens for DSLR's: rear camera port, flip mirror system, camera shutter port on the mount, camera wizard in the handset menu ...
However nowhere in the manual is there any mention of the mount's maximum load, the need for balancing the OTA etc (the altitude axis does not rotate freely and retains its position even when powered off).
Something like a Canon 450D body is quoted at 450g while my compact is only 350g. As the warranty has now expired my question is: has anyone here with a 4/5 SE mount actually used it with a similar load with no ill effects ? also did it need balancing beyond shoving the OTA toward the front as far as possible ?
I couldn't get a definitive answer out of the supplier on this issue beyond the 4SE is 'primarily for visual use, photography is seondary' and 'you may want to strap a beanbag on the front next time' (I was well aware of it's suitability for short-exposure work only before I bought it - I want to know is it fit for purpose as advertised).
I'm kind of nervous of repeating this experience again  .
thanks in advance
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Arthur Dent
Galactic Hitch-Hiker
Reged: 10/23/08
Posts: 1177
Loc: South Yorkshire, UK
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Welcome Monolith to Cloudy Nights and the NexStar forum in particular.
The altitude axis has a friction clutch and should move easily (although not "freely") with a little hand pressure but should not move when your hand is removed.
By comparison, the azimuth drive has no clutch and should NOT be moved manually UNDER ANY CIRCUMSTANCES as damage will result!
The Canon DSLR body should not cause a problem attached to the rear camera port of the 4SE, weight-wise. However, balancing the OTA is a good idea.
Remove the OTA from the mount. Attach your usual eyepiece & DSLR body.
Pop a pencil under the OTA (cross-ways) and move the OTA fore/aft until appooximate balance point is found. Mark this on the OTA (a mark on tape will do) on the top so that you can see the mark when the OTA is mounted on the fork arm.
A slight rear-bias for the weight is OK. This would ensure that the gears have minimum "slop" (aka backlash).
If the DSLR appears to have burnt the motor out again, I'd send it back for a warranty repair (as the problem repaired under warranty is still there). Seems like your scope has a fundamental weakness/fault there which should be sorted. Even if out of warranty, you have up to 6 years in UK law for a fault to be repaired if the fault was there from the outset (although proving this may be rather difficult).
Art
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If I like it, the wife says that we can't afford it!
=======================================================
Meade ETX105 (a nice "Grab & Go" scope) & Celestron NexStar 6SE with Bob's Knobs.
Various EP's from 6mm to 26mm, Baader Hyperion 8-24mm Zoom, a 2x Barlow, 2" diagonal and 7Ah PowerTank.
MRF and Antares 8x50 RACI finder scope - both for the 6SE's OTA, whilst the ETX gets a plain RDF.
Canon EOS 400D DSLR (un-modded) and SPC900 webcam. Finally climbing the AP Learning Curve!
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monolith
newbie
Reged: 09/01/07
Posts: 2
Loc: Warrington, UK
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Hi Art,
Thanks for the advice - I've experimented balancing the OTA using the pencil method with a pair of SkyWatcher 120mm dia tube rings (see here) at the front as counterweights. I can screw a binocular tripod clamp onto one of the rings for gripping a suitable weight at any angle.
The repaired altitude motor seems to be holding up fine so far (touch wood) now that everything is in near balance.
BTW I bought the rings as a much cheaper alternative to one of these from JMI for piggyback photography on the 4SE.
Presumably one should also do a Calibrate Goto when significantly altering the load on the mount
Paul
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10" LX200GPS, standard Meade 4000 eyepiece set
JMI's Wheeley bars
Kendrick Dew Removal System
Nexstar 4SE (my grab'n go) and Astrozap heated dewshield
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Arthur Dent
Galactic Hitch-Hiker
Reged: 10/23/08
Posts: 1177
Loc: South Yorkshire, UK
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No problem Paul.
A calibrate wouldn't hurt any.
Although it has a "beefier" mount than the 4SE/5SE, my NexStar 6SE's mount has no trouble with my EOS 400D added to the back end and the chunky 8x50 RACI and MRF finders attached.
Many people have lots of "goodies" attached to their 4SE/5SE's including Naglers (which weigh a tom).
Counterweights at the front can halp with balancing, although they do add a bit to the overall load on the scope's mount.
Art
--------------------
If I like it, the wife says that we can't afford it!
=======================================================
Meade ETX105 (a nice "Grab & Go" scope) & Celestron NexStar 6SE with Bob's Knobs.
Various EP's from 6mm to 26mm, Baader Hyperion 8-24mm Zoom, a 2x Barlow, 2" diagonal and 7Ah PowerTank.
MRF and Antares 8x50 RACI finder scope - both for the 6SE's OTA, whilst the ETX gets a plain RDF.
Canon EOS 400D DSLR (un-modded) and SPC900 webcam. Finally climbing the AP Learning Curve!
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