16英寸F4.5牛反系统重新设计方案,各位给提些意见。
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- 星際雲
- 文章: 20
- 註冊時間: 週四 05 1月, 2006 11:12
16英寸F4.5牛反系统重新设计方案,各位给提些意见。
先做成DOB,以后有条件上重型赤道仪,目前不算DOB底座部分重量是23KG。基本材料包括合金铝,碳纤维,底座用方铁管焊接。
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- 夸克星
- 文章: 3847
- 註冊時間: 週四 09 10月, 2003 21:06
Dear Mr/Miss Cloudy,
The OTA should be in struss form rather than straight beam cage form. Striaght beams tends to bend with different altitude angle. The alignment of the optic will be off !
There is no top cage for the secondary mirror jeopidizing it to dew formation. The lack of sufficient light shield also introduce significant amount of ambient light leakage, dropping image contrast.
For Dobsonian construction I suggest to use wood/ plywood for main construction rather than aluminium. Thin aluminium tubes tends to resonant and vibrates with a high frequency which badly deteriorate the image quality.
I also suggest you to adopt a standard design ( struss OTA, half circular altitude bearing with teflon pads, 3 teflon base point supports ) rather than you current cage/small bearing design. Standard design has huge potential to be modified into GOTO or electric driven by adding commercial available accessories ( such as ServoCAT, JMI-TNT, .......etc.). Your current design has very limited capabiliy for further GOTO modification.
A 16 incher is a very good telescoep when used visually. Hopefully you will finish your project within very short time. Remember to post it here.
Best regards
Chan Yuk Lun
The OTA should be in struss form rather than straight beam cage form. Striaght beams tends to bend with different altitude angle. The alignment of the optic will be off !
There is no top cage for the secondary mirror jeopidizing it to dew formation. The lack of sufficient light shield also introduce significant amount of ambient light leakage, dropping image contrast.
For Dobsonian construction I suggest to use wood/ plywood for main construction rather than aluminium. Thin aluminium tubes tends to resonant and vibrates with a high frequency which badly deteriorate the image quality.
I also suggest you to adopt a standard design ( struss OTA, half circular altitude bearing with teflon pads, 3 teflon base point supports ) rather than you current cage/small bearing design. Standard design has huge potential to be modified into GOTO or electric driven by adding commercial available accessories ( such as ServoCAT, JMI-TNT, .......etc.). Your current design has very limited capabiliy for further GOTO modification.
A 16 incher is a very good telescoep when used visually. Hopefully you will finish your project within very short time. Remember to post it here.
Best regards
Chan Yuk Lun
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- 星際雲
- 文章: 20
- 註冊時間: 週四 05 1月, 2006 11:12
非常感谢陈先生中肯的意见。现在这个结构最大的问题都是集中在强度问题,是否会发生变形。这在设计的时候也是比较困扰我。去年的时候曾经做过一版全桁架结构的方案,这次之所以做这个设计,考虑的主要是桁架结构的各种端头、接头过多,增加重量的同时,给加工,制作和装配带来不小的麻烦,另外连接的螺丝也不少。还有就是桁架结构下箱体部分由于重心位置的影响,得做出很长的平台板,重心位置不可调整。但强度方面肯定是最保险的,也是大家常用的结构方案。
这次做的这个6变形体方案,取自蜜蜂巢的灵感,下面的强度应该是没有问题,上面的强度主要考虑6根杆子能不能变形。这部分用的是内径27MM,外径31MM的纯碳纤管,管壁厚度2MM,感觉上这么粗的碳纤应该是够用了,但确实目前不能100%肯定。这个确实是个问题,但可以再通过增加碳纤管粗度或管壁厚度来进一步加强。但这么做带来的好处也是不少的,连接件减少很多,螺丝也减少不少,更重要是中间的安装板部分实现了上下可调,中间两个环形是可以上下移动的。通过止紧后固定。重量也减轻了不少。这个形状和安装板可调的方式给下一步上赤道仪提供了方便。
上面副镜调节部分,上园是整体切割,中间做了一个环,副镜座作为内环,中间有余量,利用三点顶丝实现中间微调,我想这样更稳固。
下面您建议的应该是DOB支架部分,这部分考虑用16*16和30*30的方钢管材焊接,异性件钢件车制后焊接。这是容易取得的材料和制作,采用外径127MM的大型轴承,做转动机构,这一部分没有经验,我会继续考虑是否合理。
这次做的这个6变形体方案,取自蜜蜂巢的灵感,下面的强度应该是没有问题,上面的强度主要考虑6根杆子能不能变形。这部分用的是内径27MM,外径31MM的纯碳纤管,管壁厚度2MM,感觉上这么粗的碳纤应该是够用了,但确实目前不能100%肯定。这个确实是个问题,但可以再通过增加碳纤管粗度或管壁厚度来进一步加强。但这么做带来的好处也是不少的,连接件减少很多,螺丝也减少不少,更重要是中间的安装板部分实现了上下可调,中间两个环形是可以上下移动的。通过止紧后固定。重量也减轻了不少。这个形状和安装板可调的方式给下一步上赤道仪提供了方便。
上面副镜调节部分,上园是整体切割,中间做了一个环,副镜座作为内环,中间有余量,利用三点顶丝实现中间微调,我想这样更稳固。
下面您建议的应该是DOB支架部分,这部分考虑用16*16和30*30的方钢管材焊接,异性件钢件车制后焊接。这是容易取得的材料和制作,采用外径127MM的大型轴承,做转动机构,这一部分没有经验,我会继续考虑是否合理。
-
- 星際雲
- 文章: 20
- 註冊時間: 週四 05 1月, 2006 11:12
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