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Nexstar 8se EQ Wedge Alignment Procedure

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#1 Don G.

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Posted 11 August 2008 - 04:35 PM

My name is Don Giandomenico and I am fairly new to amateur astronomy. A few months ago I had purchased my first scope, a Nexstar 8SE to use in my back yard to get acquainted with the night sky. It wasn’t long before I became interested in the idea of astrophotography so I researched the subject a bit to see what was involved. Polar alignment seemed to be one of the criteria for long term exposures to eliminate image rotation. Unfortunately there weren’t too many folks reporting great success in polar aligning the Nexstar Alt-Az mount. It seems that the alignment procedure would not cooperate for most or the factory Celestron wedge itself was giving them problems.

I really wanted to give Polar alignment a try to at least learn about it so I purchased the Celestron equatorial wedge (Cat #93658). After a few weeks of messing with the alignment procedure I was able to get accurate go-to performance from my Nexstar 8SE Alt-Az mount. Since then I have refined my alignment procedure and I though I would share it with others that may be interested in trying to polar align their SE mount. The following procedure is the one I developed to be used with the Celestron equatorial wedge and has worked on my scope ever since:

To start off I needed to make a few adjustments and modifications to my scope and mount. I decided to open up the Alt-Az head cover and adjust the thrust bearing nut assembly to assure that the mount arm was not "rocking" on the nylon bearing pads. This problem can cause alignment errors and make the go-to accuracy erratic. The adjustment was performed while the scope was mounted onto the wedge/tripod and the wedge was angled at 34 degrees or so (this is my local equatorial angle). Mounting the scope on the angled wedge will apply the proper side load to the SE mount and allow for proper adjustment of the thrust bearing nut. The stock bearing preload on my scope was low enough that the scope mount was "hanging" loosely and could be rocked back and fourth. This basically means that “out of the box” my scope would not work with the Celestron wedge. I fixed the problem by tightening the thrust bearing tension nut to just enough preload as to not have any play but loose enough as to not promote rotational "sticking".

Once the Alt-Az mount was “tuned up” I marked out calibration marks on the mount to indicate optical tube assembly (OTA) positioning. This would prove to really help aligning the scope and make the north equatorial – EQ autoalign alignment a breeze. I did this first by marking precise altitude index marks permanently on the mount arm. These are the same marks that are indicated by the factory stickers at the top of the mount arm. The problem is that these stickers shift even when touched lightly as they have poor adhesive under them. A permanent mark was needed to replace these stickers.

I placed the Nexstar mount with the scope attached on an extremely level surface (without the tripod attached) and used a torpedo level to align the OTA horizontally. I leveled the OTA by placing the torpedo level on the top of the OTA and then double checked it by placing the level on the bottom of the tube as well. I then used a hobby knife to make small notches (as seen in the top photo below) that line up at the precise index angle (which has the OTA parallel to the mount base bottom). I then positioned the tube perfectly vertical (perpendicular to the mount base bottom) and made a matching notch (on the round OTA dovetail clamp unit) to help aid in polar alignment.

Now all I needed was a meridian “index” indicator that would help me locate the precise meridian for alignment. I did this by carefully leveling my assembled tripod with the wedge and mount/scope attached (and angled to 34 degrees for my location). I then used the torpedo level to level the wedge base and then precisely plumb the OTA vertically in both axes (pointed at zenith). This gave me the location at which to notch the base and base cover with my meridian index indication marks. I made my notches at the upturned side of the Alt-Az mount base (as seen in the middle photo below)

To help aid in tripod setup time I added a “bullseye” level (see the bottom photo below) to the wedge base that eliminates the need for using a separate level each time I set up the scope. For this I used a 7/8” bullseye level that I had purchased from McMaster-Carr (Cat #22325A11). I drilled a recessed hole in the EQ wedge base in where I epoxied the level into (making sure to calibrate the level’s position to a torpedo level before the epoxy cures). The bullseye level makes polar alignment much easier by confirming that the wedge is level insuring that the go-to alignment will be accurate and consistent.

Continued on the next post…….

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#2 Don G.

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Posted 11 August 2008 - 04:36 PM

Continued from the previous post:

Now that the index marks have been covered I can discuss my alignment procedure:

First I “rough polar align” the scope by rotating the mount to align the meridian index marks on the base. I then rotate the OTA up to align the “zenith” marks I made which should point the scope toward the direction of Polaris (parallel with the mount arm). Using the altitude adjustment knob I center up Polaris and then fine tune the azimuth axes with the azimuth adjustment knob on the wedge. I do this with the aid of my 40 mm Baader Planetarium Sky Surfer V red dot finder and then fine tune the alignment it with an eyepiece in the scope (a illuminated crosshair reticle eyepiece will give the best results). Once the scope is pointed to Polaris I can slew the OTA to align the altitude index marks and prepare the controller for “EQ north alignment” mode. I enter my location, time and date and move onto “EQ autoalign” mode.

The controller will now ask if the scope is aligned with the altitude index marks and then ask if the scope is pointed at the meridian. I hit enter to both because the scope is already prepositioned with the marks. The controller then asks what stars to use for alignment. I chose two stars that are near zenith and yet at least 50 degrees apart. I line up my red dot finder to the chosen alignment stars and fine tune using the eyepiece to obtain my “rough” alignment. If the wedge is properly aligned and the index marks are aligned you should have very good accuracy when the scope initially slews to the alignment stars (within a few degrees). If there is a problem with any of the described steps before the scope will not slew to the desired alignment starts. It is important to solve any alignment issues before continuing the alignment process. Once the scope slews to the alignment stars I carefully center them in the eyepiece before pressing the align button. To improve accuracy I let the alignment starts “settle’ for 30 seconds or so. This allows the geartrain to catch up to the stars position and properly preload for tracking. If the star drifts out of center I carefully re-center the star before pressing the align button.

At this point the successfully aligned computer will slew to a great majority of objects to within the view of a 13-21 mm eyepiece. However you can fine tune the alignment even further by performing a “Wedge Align”. To do this you would enter the “utilities” option in the menu (after the EQ autoalign alignment is complete) and select the “wedge align” option. This is where the computer will automatically slew the scope to the “proper” location of Polaris according to the virtual star map that the computer has generated with the EQ autoalign. Once the OTA has slewed to the “virtual” Polaris location you can align the wedge’s altitude and azimuth knobs to center Polaris in the eyepiece of the scope (make sure not to push any buttons on the controller until the scope is aligned with Polaris). This procedure will set the wedge at the perfect angles to properly represent polar alignment.

Once the wedge is fine tuned I turn the controller power off and then on again to start my alignment procedure over for a final alignment. I get amazing results with the wedge aligned and the alignment stars properly centered. In fact once the wedge altitude angle is set you won’t need to wedge align again for great results. I just make sure the wedge base is level (and set to the proper altitude angle of the last wedge align) and that the scope can slew up or down to meet Polaris (just slightly above or below the “zenith” index marks on the arm). I then perform the EQ north alignment and I am good to go. Of course the wedge align azimuth angle will slowly change as the seasons pass so a new wedge align procedure may be necessary every few months.

Now I haven’t done any official long term exposure imaging with the wedge but I have used my Neximage CCD and it works great for this application especially where multiple exposures and slow shutter speed settings are required. I am able to get 60 second video captures with very little image shift or sudden jumps from the drive. Maybe in the future I will experiment using an autoguider system on my Nexstar, then I can try my hand at long term single exposures and report my findings.

Hopefully someone with a Nexstar and wedge can confirm that this procedure works outside of my experience so we have some results to compare.

Thanks for reading and clear skies everyone…

Don Giandomenico

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#3 InterStellarGuy

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Posted 11 August 2008 - 05:44 PM

2 questions I have for you.. First, youve got the wedge, but the tripod your using, is that the default tripod that comes with the SE or a heavier duty one
2. Your motor focus...is that something that replaced the focus knob completely or is it something you slid over the default focus knob?

#4 Don G.

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Posted 11 August 2008 - 09:13 PM

Hello, yes the wedge is on the stock tripod provided with the Nexstar 8se, it works great for me. I haven’t had access to the HD model to do any comparison yet. The focuser you see in the photos is a Celestron Motofocus (Cat #94142). It slides over the existing focus control knob adjuster post. I had shortened the motor focuser a bit to clear the Alt-Az base by removing a center adaptor piece and shortening the mounting skirt. The aluminum drive cup on the focus motor fits the 8se focus knob perfectly. The plastic barrel that connects the motor to the screw on mounting base on the OTA needs to be trimmed a bit to make the connection. This modification was done using my 7 x 10" lathe but could probably be duplicated with a hacksaw and file set.

You may also notice that the eyepiece tray on the tripod is larger than the stock one. I made this new tray out of 1/4" masonite and painted it black. It rests on the stock tripod support spreader. There is also a Velcro accessory bar that I attached to the wedge base. I made this bar out of 1/4" x 1" bar stock and covered the bottom half with 2" Velcro. It holds the focus controller as well as the hand controller much like a "wing thing" setup.

Don

#5 Tel

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Posted 12 August 2008 - 05:21 AM

Hi Don,

Congratulations on a great piece of work in, without doubt, discovering a means of getting the standard wedge / single tine SE mount to function satisfactorily.

I don't know if it's possible (without rewriting), but I for one would like to see this valuable method description duplicated as a CN official article (see home page -- submit a report / review, and equally placed on this forum under "Alignment Tips Here"). Maybe someone can advise how this might be done.

Following this excellent work, there are one or two points I would like to raise with you for my own interest, relating to Polaris versus true NCP alignment.

I'm absolutely convinced that from your work a very significant step forward has been made in wedge alignment but in the final analysis, your alignment, (according to the Celestron procedure for wedge alignment), is made on Polaris.

In other words, there is no provision (for example, polar 'scope alignment), in wedge alignment to make further adjustment to attain the exact NCP except for the protracted and tedious drift method.

I have recently been trying to establish a method of bringing the usual "rough" alignment on Polaris nearer to the NCP by the same method a polar 'scope employs but without actually having to use one.

There have been various methods written on this subject (Clay's Kochab Clock" being one of them), but I just wondered if you had any views on the subject ?

Once again, Don, a really fine article !

Best Regards,
Tel

#6 Don G.

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Posted 12 August 2008 - 09:55 AM

Hello Tel, and thanks again for the very kinds words :0) Your NCP question is a great topic to discuss here. I feel the best way to take advantage of polar alignment is to have your wedge as accurately positioned as possible. This will keep the scope tracking on your objects more accurately with little altitude adjustment from the computerized mount.
This is one of the strong advantages polar alignment has over Alt-Az mounting as the Alt-Az computer really needs to do a lot of math to keep an object in view as it passes near zenith. The Alt-Az computer must continually be moving both axes of the mount at continually changing rates to keep the object in view.

Polar alignment fixes this problem but is not always easy to obtain granted that the best indicator we have for the North Celestrial Pole (NCP) is the star Polaris which is ¾ degree off of the true NCP. Several methods were created to properly identify the location of the NCP but require more effort than most wish to endure when setting up their scopes. It seems that most folks choose to align their portable scopes with Polaris out of sheer convenience and forgo the tedious task of finding the NCP.

Unfortunately aligning your mount with Polaris puts a very small tilt in the axes of your mount. This small tilt can cause image drift simply because the mechanics of the mount are not that accurate to compensate for very small altitude movements. This is even more evident when small changes in direction are lost in drive gear backlash. In my opinion you will get the best tracking when the scope is continually tracking with right ascension and having minimal altitude adjustments.

Now it seems the trick is to get proper NCP alignment without spending half the night properly locating it right? Well I feel the Celestron did a great job with their “Wedge Align” function in their SkyAlign software. With this function you can locate the NCP and align the wedge accurately to it with minimal effort. The way the wedge align utility works is the computerized controller (once aligned properly) takes into account where the true NCP should be based on the virtual sky map it generates during alignment. The computer then slews the scope to the direction of Polaris which has been physically offset from the true NCP. In fact the scope will slew to Polaris and it will be ¾ degrees in the opposite radial direction of the true NCP.

This offset that the computer adds to the scopes position compensates for the location of the true NCP and allows you to realign the wedge to point the scope to Polaris (this of course is done without electrically slewing the scope’s mount). Once this alignment is complete the mount should be perfectly polar aligned (3/4 degrees from Polaris to the NCP). You can then perform an EQ north alignment for an accurate polar alignment.

Now the angle of declination for your wedge will always stay the same if you are viewing from the same location. This means that once you set your wedge altitude angle (using the wedge align utility) for your location you should not have to adjust it again granted that your tripod is level. My wedge is set for 34 degrees positive DEC. Unfortunately the wedge azimuth angle which points to the horizontal location of the NCP will need to be set every time you set up your scope. This will need to be done using the aid of Polaris and the wedge align utility.

I personally do not wedge align every time I use my scope. In fact I just level my tripod and use the altitude axes of my scopes to line up with Polaris. This alignment gets me close but is not really that accurate. This is because Polaris is continually rotating around the NCP and depending on what time of day or season you align with Polaris can put the NCP on the left or right (top or bottom) of Polaris. When I align my scope I try to use the position of the big dipper as a reference to what angle Polaris is to the NCP. This helps me to “time” my alignment as to keep it similar to previous evenings. However it is apparent that a new wedge alignment will be necessary as the seasons progress and the NCP will cycle around Polaris as each night passes.

Now I still am impressed with the alignment capabilities of the Nexstar’s computerized mount. Even with simple alignment on Polaris I can get great go-to accuracy granted the scope is positioned correctly on the meridian and altitude index marks before seeking alignment stars. This just goes to prove that Celestron really created a truly dynamic alignment system that can compensate for many variables.

Please feel free to correct me if I haven’t used the proper terminology, I am still learning this stuff :0P

Oh, here are a couple of images I took of the moon for fun....

Thanks for reading and clear skies!!!

Don G.

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#7 rick rian

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Posted 12 August 2008 - 11:19 AM

Hello Don and a hearty welcome to Cloudy Nights and in particular the NexStar forum!

Well, it looks like you have successfully documented a workable EQ wedge alignment procedure ... kudos to you! This is the first Nexstar mount/wedge alignment devoted article I've ever seen, thanks for that! Excellent job putting your information and photos together, that really helps bring it all together, at least for me ... :grin:
I'm very happy the process is working for you.

Thanks also for taking the time to share this with us and please keep up the great work sir!

This will be an interesting thread to follow !!!

Again, welcome aboard!

#8 Tel

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Posted 12 August 2008 - 01:08 PM

Hi Don,

Thank you for that comprehensive description of NCP alignment using your 8SE /wedge set up. I just need a litle time to digest all that information before I make a response. Bear with me for a short time then if you will.

By the way, those are some nice lunar landscapes you've provided using your Neximage. If they are merely the result of stacked raw frames, then I would say you don't have much of a problem with focusing !

Best Regards,
Tel

#9 Don G.

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Posted 12 August 2008 - 03:00 PM

Hello Rick, thanks for the warm welcome. Hopefully I will be able to contribute to the forum more often.

Tel, those images were processed in RegiStax from 300 frame AVIs. There was quite a bit of thermal disturbance in the video when I took those. It kind of looked like you were looking through a bubbling pot of mineral oil :0P

Cheers…..

Don

#10 Tel

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Posted 13 August 2008 - 11:08 AM

Hi Don,

Thanks once again for your above post on the subject of NCP alignment. Before commenting however, I have to confess that I aways have great difficulty getting my head around celestial mechanics ! :question: Still, I'll try to put my understanding of this particular aspect of it to the test !

There are, as you've pointed out, a lot of influencing factors involved in attaining polar alignment good enough for prolonged exposure astro-photography : spur gearing rather than worm drives being a prime example.

However, from what I've read, both within your post and from other sources,(noteably the 8SE and my own N8i manual), my understanding is such that according to the writings of Celestron, the OTA and the single arm are apparently separated by ca. 0.75 arcdegs.; the distance between Polaris and the true NCP so that when the final wedge adjustment takes place, alignment on Polaris itself automatically sets the NCP via this offset between OTA and mount arm (presumably in much the same way as a polar 'scope would on a GEM).

If this is the case, a polar 'scope, as far as I know, will bring the polar axis of the mount to within about 5-7 arcmins. of the NCP.

Do you think that the Celestron wedge can produce comparative accuracy, presupposing of course, I've got the principle right ? :question:

Best Regards,
Tel

#11 Don G.

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Posted 14 August 2008 - 12:04 AM

Hello Tel, The way I understand it is that there is nothing physically added or angled into the Alt-Az arm to do any compensation for polar alignment (if I am understanding you correctly?). It is all done through a DEC-RA coordinate that the computer "adds" to the existing alignment to compensate for the position of the NCP as it is positioned in relation to the computer’s virtual sky map at that current time and date of alignment.

During the “wedge align” procedure the Alt-Az arm and OTA together are slewed raidialy away from the true NCP passing directly over Polaris for a total of 1.5 arcdeg from the existing alignment position of the NCP (0.75 arcdeg from the existing alignment position of Polaris). By manually moving the mount/scope to align with this “new” location of Polaris it should bring the NCP into axial alignment with the wedge. At this point a new "north EQ autoalign" must be performed to make use of the new wedge align.

However it is very important that the proper “index” marks for the meridian and altitude are used when aligning the scope the first time or the computer will be thrown off by improper reference points. I’m really no expert in this area considering I only have a few months of experience but I do know that I am getting good results with this system.

Unfortunately I have never used a polar scope so I can’t compare the methods just yet. Give me some time and I will try to brush up on the different equipment some more :0)

Cheers,

Don

#12 Tel

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Posted 14 August 2008 - 06:27 AM

Hi Don,

That is extremely interesting what you say about the 1.5 deg. slew over Polaris. May I ask where you got this information ? I have to say that I have never come across it before.

I must confess that I've always worked along the lines that in performimg an EQ North Alignment, the 'scope makes it's "picture" of the current sky in much the same way as it does when carrying out any Alt./Az. alignment: wedge alignment being a further option to increase accuracy.

Thus my limited experience told me that each time I made a successful EQ alignment and then slewed to Polaris, it would be in the FOV of say a 25mm EP but not necessarily centralised in it. I therefore had the option of accepting this and this "very rough" alignment as a whole as basically "suitable" for viewing, or I refined it by using the wedge align feature.

"Wedge align" to me therefore, was merely a centralisation of Polaris in my EP by moving mount and/or tripod rather than OTA so that I was now "spot on" Pole Star alignment.

Furthermore my thinking was such that the only relationship this bore to the NCP, was that it was about 45 arcmins. adrift from it and that in the absence of a polar 'scope, which might bring me to within, say, about 5- 7 arcmins. of the NCP, my only recourse to obtain greater accuracy would be to drift align.

That WAS the way I saw it Don. Since then I of course came across and read with much interest your recent treatise on the matter and saw many of the ways which might have compounded my rejection of wedge mounting these 'scopes per se.

But to reiterate, I never knew that from what you have said, wedge alignment was bringing something more to the party than merely a Polaris alignment.

I would be very interested to hear any further views you might have so that I might learn more.

Many thanks and best regards,
Tel

BTW. If you're not familiar with the workings of a polar scope, it is a small one that passes though the polar axis of an EQ mount.

It requires accurate centralisation to ensure it is parallel with the axis in much the same way as a finder 'scope might be aligned with the main OTA.

Once aligned, it is then calibrated so as to be able to determine Polaris' position relative to the NCP at any given date and time.

Thus on any evening, having set up the GEM so that Polaris is in its FOV, the star is merely scale offset from its initial position at the centre of the 'scope by the required amount and direction thus bringing the mount all the closer to the NCP.

#13 Don G.

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Posted 14 August 2008 - 07:18 AM

Hello Tel, actually the 1.5 deg is something I tried to use to describe how the scope slews in relation to the NCP and Polaris. In reality the scope should only "slew" 0.75 from Polaris but will also be 1.5 from the NCP when done. This figure was only used to try to maybe explain direction of offset. There could be something I am seriously missing here in my logic.

Unfortunately it was probably a bad idea for me to be the one to spearhead such a technical thread when I have not the experience or background to do so. I can only offer my apologies to anyone if I have confused them in any way.

Don

#14 Tel

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Posted 14 August 2008 - 11:32 AM

Hi Don,

No apologies please, ! Certainly not as far as I'm concerned !

I think what you've achieved in making EQ and wedge alignments "work" with these 'scopes is absolutely splendid and should encourage everyone who possesses or were ever contemplating buying a wedge but instead listened to my condemnations, to reconsider !

For me however, your message came somewhat too late ! I'd already bought myself that HEQ5-Pro with which, (and with the best will and applied technique in the world), I have to say, the Celestron mount and wedge can never compete !

As to where we stand on the NCP/ Polaris alignment issue using the wedge, I am now uncertain. I think at least for the moment, I'll stick to my view that accepting, if aligning in Alt./Az. mode, a star or object more than often does not hit dead centre in an EP, then despite all measures taken to ensure accuracy of alignment in EQ mode, why should it be any the more accurate ?

I therefore still believe that a wedge alignment carried out after having placed Polaris in the FOV of, say, a 25mm EP following an EP North alignment, is merely using this ideally placed star to then produce the best of a rough alignment and that the only way forward from that point to a more precise alignment, nearer to the NCP, would be via the drift method.

That is in short to sat that I personally don't believe the NCP can be attained by mere wedge alignment alone but that it will achieve an alignment to somewhere probably within ca. 0.75 degs. of it by centering Polaris.

Best Regards,
Tel

#15 rick rian

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Posted 14 August 2008 - 12:14 PM

... Unfortunately it was probably a bad idea for me to be the one to spearhead such a technical thread when I have not the experience or background to do so. I can only offer my apologies to anyone if I have confused them in any way ...


I agree with Tel and disagree with your statement above Don. What you have accomplished with the wedge, 8SE and NexImage is remarkable! :bow:

Don't sell yourself short, you've opened a door here that has been half-open for a long time. Some of us have had NO luck in getting the EQ align and the wedge to work anywhere close to what you have acheived. I suggest we take some time, go through your process and see what works for others. Obviously your success is uplifting to say the least.

Please keep up the good work, and I'll do my best to keep up! :grin:

#16 solidrock

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Posted 04 October 2008 - 10:36 AM

can you please tell me - which way should the wedge be pointed when you start a polar align? (which is the front of the wedge?

#17 Tel

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Posted 04 October 2008 - 11:15 AM

Hi Solidrock,

The altitude adjustment screw of the wedge is placed between two legs of the tripod. The third leg is normally considered the "North" leg (in the Northern hemisphere) and is aligned with the NCP (Polaris to all intents and purposes).

In any event the attached link should explain all you need to know and more about wedge alignment. It refers to the erstwhile Nexstar 8i but just read across. It's the same.

http://cloudynights....s/nexstar8i.pdf

Hoping this helps ,
Best regards,
Tel

#18 rick rian

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Posted 04 October 2008 - 04:24 PM

Hi Solidrock,

What Tel says, and a very warm welcome to Cloudy Nights!

I'm happy you decided to join the group.

#19 Tel

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Posted 04 October 2008 - 05:24 PM

Hi Solidrock,

Rickster has reminded me yet once more ! :bow:

My apologies. :o

It was very remiss of me not to welcome you primarily to CN. :foreheadslap:

A very warm welcome therefore, from me too ! :jump:

Best Regards,
Tel

#20 solidrock

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Posted 04 October 2008 - 05:29 PM

Thanks for the info. It was helpful. I am a sad case of going out and buying a bunch of Astronomy equipment and not really knowing the basic. atleast I have a lifetime to practice. :) Thanks again!

#21 Reggie

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Posted 05 October 2008 - 08:53 AM

Hi Guys, I built myself a wedge for my 6Se scope and mount, it's the same mount/tripod as the 8SE, so I feel I am able to comment on some of what has been said here.

No one has mentioned at all about how close to NCP their alignments are according to the 'Display align' function, any chance you could guys could report that here?

My last alignment on the wedge (EQ north, 2 star, NO WEDGE ALIGN) got me to within 20mins on one axis and 11mins on the other, this is of course by eye, I have got closer than this, and can tweak it by doing a 'Wedge align' getting close to 1min on either axis if I take my time. I don't usually bother doing a wedge align as anything around 15min in either axis has been good enough for me (I'm autoguiding but thats another story) with this I can accomplish at least 5min subs when doing deep space astro photography (Images of setup and DSO at the bottom of my post).

The way I understood the manual is that the wedge align method treats the OTA as a polar scope, how accurate this will be is determined by how much play you have in your bearings, goto approach and backlash.

Here's a pic of my setup:
http://i246.photobuc...WO66imaging.jpg

and a few DSO that I have managed to capture using my setup,
M45
http://i246.photobuc...ndStuff/NEW.jpg

Gamma Cygni Nebula
http://i246.photobuc...ff/gamcyg2b.jpg

NGC0457, The owl cluster
http://i246.photobuc...tuff/NewOwl.jpg

M27, The Dumbell Nebula
http://i246.photobuc...uff/m27crop.jpg

M31, Andromeda Galaxy
http://i246.photobuc...tuff/PB_M31.jpg

M57, The Ring Nebula
http://i246.photobuc...ff/blergh2b.jpg

M33, Triangulum Galaxy
http://i246.photobuc...tuff/m33db3.jpg

#22 rick rian

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Posted 06 October 2008 - 02:01 PM

Hi Reggie,

Very interesting photo of your home built wedge and entire set-up. Would it be possible for you to post more photos of your setup, from different angles, so we can see exactly what you're working with?

Excellent images, BTW. :waytogo:

#23 Reggie

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Posted 07 October 2008 - 06:24 AM

Hi Rick, sure, I'll get some more images for you a little later today, anything in particular you'd like an image of?

#24 rick rian

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Posted 07 October 2008 - 09:22 AM

All sides and details of the wedge itself. Anything you might find interesting to share.

8x10 glossy would be nice, sorry I couldn't resist that! :grin:

Thanks, Reggie!

#25 Reggie

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Posted 07 October 2008 - 09:43 AM

Ok, well to kickstart this I'll detail the wedge and then get you some snaps.

The wedge is made from marine ply, Az adjustment is via loosening 3 bolts and moving by hand, Alt adjustment is acheived by adjusting the length of the north facing tripod leg. the main wedge plate is set to about 39deg (the opposite to my lat. of 51). There is a small space underneath the wedge plate that houses my homemade dew heater controller + 12v 7ah battery which you can also see in the picture.

This setup requires a weight system for balance to counter the weight of the WO 66 scope and 450d dslr at or close to zenith, as you can see from the barbell weight hanging off the bottom of the ota :)

I'm going to address the az aligment issue at some point by putting a couple of adjustment bolts on the bottom of the wedge either side of the tripod top plate as it would be far easier than my current method.






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